An aqueous gel called ultrasound gel, or an ultrasonic gel, is used in ultrasound diagnostics. It is put on skin surfaces to form a seamless contact between the skin and the ultrasound transducer (probe). This is because ultrasound waves propagate poorly in air. It eliminates any air bubbles, so sound waves obtain a pathway into the body tissues, allowing for accurate imaging of int... https://www.gstc.com/product/ultrasound-gel/