These pads having size of 50mm x 50mm come in a single pack, (total 4 electrodes in a package), Use for any body part. For use with TENS (transcutaneous electronic nerve stimulators) and EMS (electrical muscle stimulators) as well as any compatible pulse massagers. These Electrode Pads are professional grade, made with the highest quality adhesive gel for maximum reusability. It can be used easily for 35-45 times of use (each time you stick in on the skin and remove it, it is counted as one time). They are designed to provide comfort while delivering the most efficient treatment. UltraCare PRO Electrode pads are durable, comfortable and gently adhere to your skin.