Electrodes, TENS, Misc. - Sonigel Ultrasound couplet, 5 liter bottle : Sonigel is a clear, colorless, nearly bubble-free gel or as a soothing lotion with Aloe Vera. All Sonigel products are alcohol and salt free as well as non-corrosive. The gel is convenient for either therapeutic or diagnostic ultrasound procedures. The lotion is greaseless and can also be used for massage therapy.