40 individual 2"x2" OTC Electrodes. Therapist's Choice FDA CLEARED OTC medical-grade TENS electrodes are high quality, premium TENS Electrodes made with high quality adhesive for reusability. These TENS Unit Electrodes are professional quality and very popular with Healthcare practitioners for in-house use with their professional electrotherapy devices. They also make a preferred choice for personal use TENS Unit. These TENS Electrodes offers the highest quality of reusable gel on the market. Since the Electrode Pads are pre-gelled, simply place them on the area, and when finished, place them back on the electrode pad (included). The better you care for the electrodes, the longer they will last.