• Operating Temperature: -70 °F to 450°F (-56°C to 230°C)
  • Halogens and Sulfur: less than 50 ppm
  • Auto ignition Temperature 628°F (331° C)
  • Flash Point: 255°F / 124°C
  • Surface Tension 36 dynes/cm (mN/m), 77°F (25°C)

Echo 4 HT™ is a fluid ultrasonic couplant, ideal for pumping and automated crawlers and thickness gauging of smooth or polished surfaces.


Broad operating range -70 °F to 450°F (-56°C to 230°C)
Water soluble: easier to remove than most fluid ultrasonic couplants by wet or dry wiping or water wash.
No “oil slick” when used where couplant may drip into a body of water.
Low toxicity
Compatible with a broad range of materials including most metals, plastics and composites
Good Surface wetting due to low surface tension and solvent properties.
Slow Drying at ambient temperatures

Contains no glycerin which can interfere with subsequent penetrant inspection.

Environment and operator friendly – no formaldehydes, nitrates, nitrites or glycol ethers.

Minimal residue

Removal: Wipe with wet or dry paper or cloth rag or water wash.

Echo 4 HT