Cygnus 4+ General Purpose

Ultrasonic Thickness Tester

A metal thickness tester used for a wide range of applications.  This thickness tester offers: an A-scan display; sequential data logging; 3 versatile measuring modes and; a high temperature probe for measuring remaining wall thickness in high-temperatures.

Key features of the Cygnus 4+ General Purpose ultrasonic thickness tester include:

  • Multiple-Echo for accurate through-coat measurements, as specified by Classification Societies
  • Echo-Echo and Single-Echo modes for heavily corroded metals with a thin or no coating
  • Measurements can be taken on hot surfaces, up to 300°C, using the NEW Cygnus High Temperature Probe
  • Deep Coat function ignores coatings up to 20 mm thick
  • MSI™ helps verify stable and reliable measurements
  • Manual and automatic gain control
  • Min/max measurement limit functions with visual and vibrate alert
  • Large front sunlight readable LCD display with live A-scan
  • Water and dust tight IP67 housing
  • Shock and impact proof to US MIL STD 810G
  • Safe operation in explosive atmospheres: Class 1, Division 2, Group D locations only, as defined in NFPA 70, Article 500
  • One and two point calibration
  • Can be upgraded to 6+ at an additional cost.

High Temperature Measurements

  • Using the NEW High Temperature Probe, measurements can be taken on hot surfaces of up to 300°C
  • No cooling period required – reducing inspection time and facilitating more effective measurement
  • Option to use standard cable or more robust, braided cable.

Basic Data Logging

  • Linear based data logging
  • Eight user-defined comments to attach to any measurement point
  • Auto-log feature
  • Saves measurements and A-scans
  • Records stored on SD card
  • CygLink software used to transfer and manage data.

Three Versatile Measuring Modes

  • Multiple-Echo mode uses three error checked back wall echoes to provide the most reliable and accurate remaining thickness measurements, with no need to remove coatings (up to 20 mm thick).
  • Single-Echo mode is ideal for measuring uncoated metals with heavy front and/or back-wall corrosion. Also effective on a range of cast metals, plastics and composites.
  • Echo-Echo mode works best for measuring heavily corroded metals through thin coatings of up to 1 mm thick, ideal for measuring painted metals with heavy back wall corrosion.

CygLink Software

CygLink is a Windows® based application used to transfer and manage data logger records, A-scans, measurement comments and material velocity tables. The program can generate PDF reports and export to Excel. It also displays A‑scans, allowing for after-the-event analysis of logged measurements.

MSI™ (Measurement Stability Indicator)

Exclusive to Cygnus, MSI™ ensures stable and therefore, reliable measurements are displayed in Echo‑Echo and Single-Echo modes.

Multiple-Echo Mode Ignoring Coatings up to 20 mm Thick

Measuring Heavily Corroded Metals

Echo-Echo Mode Ignoring Coatings up to 1 mm Thick

Impact Test of a Cygnus Ultrasonic Thickness Tester

Water Resistance Dunk Test of a Cygnus Ultrasonic Thickness Tester

Water Resistance Hose Test of a Cygnus Ultrasonic Thickness Tester

Large Bright LCD Display on Cygnus 4, 4+ and 6+ Ultrasonic Thickness Testers

Large LCD Display and Simple Menu Operation on Cygnus Ultrasonic Thickness Testers

Measuring Uncoated Small Diameter Pipes

Measuring Small Diameter Pipes Through Coatings

A-Scan on Corrosion

Measuring ModesMultiple-Echo using 3 echoes to ignore coatings up to 20 mm thick
Echo-Echo using 2 echoes to ignore coatings up to 1 mm thick
Single-Echo using 1 echo
MaterialsVelocities from 1,000 – 9,000 m/s
Accuracy±0.05 mm in Multiple-Echo measurement mode, when calibrated and measuring the same material as calibrated on
±0.1 mm or 0.1% of thickness measurement whichever is the greatest – in Single-Echo & Echo-Echo measurement modes, when calibrated and measuring the same material as calibrated on
ResolutionMultiple-Echo mode – 0.1 mm or 0.05 mm
Single-Echo and Echo-Echo modes – 0.1 mm or 0.01 mm
Probe OptionsSingle Crystal Probes
Twin Crystal Probes
High Temperature Probe
Measurement Range in Steel0.8 – 250 mm depending on selected probe and configuration, material and temperature
Connector2 x Lemo 00
Power3 x AA / R6 batteries
Battery LifeApprox. 10 hours continuous measurement
ElectronicsDual channel pulser
Display2.4 inch QVGA LCD: 47 x 37 mm
Size84 x 130 x 35 mm
Weight300 g (inc. batteries)
Operating Temp.-10°C to 50°C
Data Logging5,000 measurements and A-scans per record. Max number records: 100 (soft limit)
Computer SoftwareCygLink allows remote logging and viewing of A-scan graphs
Survey and report generation to PDF file
Graphic analysis of data and statistical calculations
Environmental RatingIP67
Safe operation in Explosive Atmospheres: Class I, Division 2, Group D Locations only, as defined in the National Fire Protection Association Code (NFPA 70), Article 500. Tested using MIL-STD-810G, Method 511.5, Procedure I
MIL STD 810G Method 501.6 (high temp +55°C (131°F))
MIL STD 810G Method 502.6 (low temp -20°C (-4°F))
MIL STD 810G Method 507.6 (humidity 95%)
MIL STD 810G Method 512.6 (immersion 1 metre for 30 mins)
Shock and ImpactMIL STD 810G Method 514.7 (vibration)
MIL STD 810G Method 516.7 (shock 20g)
MIL STD 810G Method 516.7 (transit drop 1.22 m)
StandardsDesigned for EN 15317
ComplianceCE, UKCA, RoHS
Warranty3 years on tester
6 months on probe

Basic kit for the Cygnus 4+ General Purpose ultrasonic thickness tester includes:

Instrument body, operating manual, neck strap and accessory pouch that contains 3 x AA batteries and blue couplant gel.

Single element probe kit for the Cygnus 4+ General Purpose ultrasonic thickness tester includes items listed in basic kit, plus:

Ultrasonic probe, moulded probe cable, 15 mm steel test block, spare membranes, membrane key and membrane couplant.

Twin element probe kit for the Cygnus 4+ General Purpose ultrasonic thickness tester includes items listed in basic kit, plus:

Ultrasonic probe and moulded probe cable.

Weight5 kg

Cygnus 4+ General Purpose Standard Kit WITHOUT PROBE (050-4500/5), Cygnus 4+ General Purpose High Temperature Kit with Probe T5B-MAUH 5MHz Twin Element & Twin Lemo 00 to Microdot Lead (050-4502/5)

To compliment Cygnus’ range of ultrasonic thickness testers we offer a range of portable UTM probes. The performance of any ultrasonic thickness tester relies heavily on the probe and its suitability to the material being tested. Therefore, selecting the right probe is vital.

All Cygnus’ portable UTM probes are made from stainless steel and have a hard wear face or a wear membrane to protect the probe.

Variety of Cygnus INOX Probes

  • Stainless steel Single Crystal probes: Uses multiple-echo mode, includes replaceable membranes for long life, require no zeroing and have a high linear accuracy.
  • Stainless steel Twin Crystal probes: Uses echo-echo and single-echo modes and have improved measurability on extreme back wall corrosion and pitting.
  • Probes for use with the Cygnus 2+, 4, 4+ and 6+ testers are fitted with a BNC or Lemo 00 connector.

Single Crystal Probes

HT Probe


Twin Crystal Probes

High Temperature Probe

Twin element ultrasonic probe designed for high-temperature, in-service thickness measurements and corrosion surveys across oil and gas, refining, energy and process sectors.

  • No cooling period required – reducing inspection time and facilitating effective measurement
  • For use on hot surfaces up to 300°C
  • Measures remaining wall thickness from 1.5 to 250 mm – depending on temperature and material.

6 reviews for Cygnus 4+ General Purpose

Avatar Of Dimitrios Y.

Dimitrios Y.

Dec 02, 2015 9:50 AM

We tested the New Cygnus UTM Instruments 2+ and 4+ using single & twin crystals probes.

Tests carried out in our premises and in real working conditions on a 15 years old cargo ship of 10.000 M.Tns.

In our premises we used the following samples, which have been obtained from ships; cropped plates and we use them in our premises for practice purposes.

1.New Coated Steel Plate 10.0 mm.
2.Extremely corroded on both sides Steel Plate, with thickness variation from 4.6 mm to 9.7 mm. Taken gaugings were verified with Outside Callipers.
3.Gray Cast 12.0 mm.
4.Aluminium 6.0 mm.

On the Cargo Ship we focused our tests on the non-coated Inner Bottom Plating of 16.0 mm original thickness.
We got about 100 gaugings which varied between 15.8 mm to 14.4 mm.

All readings, in both tests, were obtained instantly and it should be mention that the new measuring experience with MSI System gave to us a real confidence that the reading we see is the real remaining thickness on that spot.

Apart the user-friendly, high analysis coloured LCD screen and the very easy menu we consider quite important to mention that once we took the instrument in our hands we got an immediate impression of the unit being very rugged. Its tight case together with the strong cable and its twin lemo locking connector allow the operator to focus only to the gauging without worrying at all about the machine.

Avatar Of Jim P.

Jim P.

May 24, 2017 9:51 AM

We approached Cygnus in late 2016 as a result of discovering areas of corrosion in our vessel Lord Nelson in an area specific to the design allowing for disabled access – the watertraps. These areas act to prevent the ingress of water into the vessel given that we can’t have door sills due to the flat sill required for wheelchairs.

Given the age of Lord Nelson, now over 30 years old, it was agreed that to have our own NDT test instrument, while not negating the need for formal Lloyds’ testing, would allow us to keep a check on corrosion and give us a level of confidence as and when areas were discovered. Cygnus kindly offered advice and supplied a Cygnus 4+ Ultrasonic Multi-Mode Thickness Gauge kit including both single and dual crystal probes.

Despite our own relative inexperience in such testing, the results we obtained were confirmed by professional spot testing and proved easy to achieve, the device being simple to calibrate and use, with both probe types.

Avatar Of J D Howard

J D Howard

Jun 20, 2017 9:51 AM

I have used the gauges extensively, often in awkward places where the gauges often take a beating, as well as occasionally getting wet; but the Cygnus gauges have proven to be robust and reliable.

The 4+ meter is very light and easy to carry and has the option to use single crystal or twin crystal transducers, which allows me the ability to measure through thick coatings in deep coat mode, as well heavily corroded metals. When taking measurements with this meter I have found it to be accurate with repeatable results.

The 4+ gauges we use at JDH allow us to see a clear, simple A-Scan as measurements are taken – which in turn allows us to verify measurements. I can also log my measurement [together with the A-scans] and easily transfer them into reports for clients, which is very beneficial.

I am pleased to say that I have always received excellent service from Cygnus Instruments and I will continue to use their products, as I know I have a reliable, robust tool that I can genuinely trust.

Avatar Of Blagoja S.

Blagoja S.

Oct 01, 2019 9:52 AM

We have purchase 4 pcs. of Cygnus 4+ UTG Kit and 1 pcs. of Cygnus 6+ UTG Kit.
With these instruments we have check more that 3.000.000 points on coated steel pipe. Results were among expected. We are more than satisfied with equipment.

Avatar Of Dale B.

Dale B.

Apr 23, 2020 9:52 AM

Having owned and operated the Cygnus models two and three I recently upgraded to the Cygnus 4+. Cygnus has always been a brand to associate with reliable and accurate UTM readings, and working for a number of high-profile clients and MCA classification societies this accuracy is mandatory. The Cygnus 4+ is not only small and light weight, it is also wrist mounted to keep your hands free. The added functions are endless, and you can add comments in for single readings and also add additional readings (outside of the pre-determined grid) in as you are conducting the survey. This is very useful if defect areas are identified as they can be clearly documented on the spot, rather than having to return after the record is completed. The back-office software is user friendly and has plenty of fields for extra information that can be added apparent to the vessel. After having a demonstration of the Cygnus 4+ at the 2019 Seawork show I ordered the unit the following day. The staff are very helpful and knowledgeable, and the unit arrived promptly. The Cygnus 4+ has helped me become more time efficient and produces a very informative report that is well accepted within the industry.

Avatar Of Mr Monsores

Mr Monsores

May 06, 2020 9:53 AM

I have already used CYGNUS equipment, they are practical equipment and with excellent response in thickness measurements. Very good brand.

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