Sigma 342A is a compact handheld, high-precision ultrasonic thickness gauge designed for accurate non-destructive measurement of material thickness from one accessible side using ultrasonic pulse-echo technology, particularly for field inspections in marine and industrial environments. It combines advanced single-chip microprocessor technology with user-friendly functionality for reliable field measurements

It is widely used for corrosion monitoring, quality control, and preventive maintenance because there is no need to cut, dismantle, or damage the component..

Key Features
High Resolution: Measurement resolution up to 0.01 mm for precise readings.
Wide Measuring Range:
1.0–350 mm (45# Steel)
Optional 0.8–500 mm (45# Steel)
Dual Frequency Operation: 5 MHz standard / 2.5 MHz (with special probe).
Continuous & Single Measurement Modes
Sound Velocity Measurement & Adjustment
21 preset material velocities
Manual adjustment (1000–9999 m/s)
Automatic Probe Recognition
Data Storage: Up to 100 measurements
Custom Thickness Alarm with buzzer alert
MAX / MIN / AVG display
Self-Calibration Function
Accuracy & Performance
±0.05 mm for thickness <10 mm
≤±(0.01 + H/200) mm for 10–99 mm
≤±(0.1 + H/100) mm for >100 mm
Minimum tube curvature: Ø20 × 3 mm (45# Steel)
Design & Power
Lightweight: 153 g (without batteries)
Compact Dimensions: 72 × 135 × 36 mm
Power Supply: 3 × 1.5V AA alkaline batteries (approx. 20 hours operation)
Operating Temperature:
Main unit: 0°C to 40°C
Probe: 0°C to 60°C

Sigma 342A is intended for non-destructive thickness measurement of metallic and many non-metallic materials. It includes preset sound velocities for numerous materials, manual velocity adjustment, automatic probe recognition, and optional lower-frequency probes for thicker sections.

Applications
• Marine hull thickness inspections (Bottom shell, Side shell, Deck plates, Double bottom, Bulkheads)
• Dry-dock inspection
• Corrosion monitoring
• Pressure vessels and pipelines (Pressure vessels, Heat Exchangers, Steam drums)
• Structural steel evaluation of Structural beams, Plates, Columns, Bridges, by measuring remaining thickness after years of service.
• Pipe wall measurement (Carbon steel pipes, Stainless steel pipes, Copper pipes, Aluminum pipes)
• Stainless Steel Tanks wall thickness inspections
• Castings (Cast iron, Nodular cast iron, Aluminum castings) Checking for Uniform thickness, Manufacturing quality
•  Preventive maintenance programs (Annual shutdown inspections, Preventive maintenance, Asset integrity programs)
• Condition monitoring
Materials supported : Sigma 342A provides preset acoustic velocities for approximately 21 materials, with manual adjustment over a wide range (1000–9999 m/s).
Typical compatible materials include:
Carbon steel
Stainless steel
Cast iron
Nodular cast iron
Aluminum
Copper
Brass
Zinc
Titanium
Glass
PVC
Polyethylene
Other homogeneous materials after velocity calibration.

Sigma 342A's combination of portability, precision, and intelligent measurement functions makes it a practical solution for surveyors, engineers, and maintenance professionals requiring dependable ultrasonic thickness measurements in demanding environments.