A Selection of Ultrasound gel for medical use from Parker Laboratories and Wavelength. Gel such as Aquasonic 100, Aquasonic Clear, Spectra 360 (can be used with carbon electrodes used with TENS units, IFC, & NMES) are all a fantastic product for general physical therapy practices. Parker offers Aquasonic 100 in both non-sterile and Sterile packets for single use applications.