The Compex Easy Snap Performance 2in x 2in Electrodes replace the worn-out electrodes on a variety of electrical muscle stimulation devices (check specs for compatibility). They're small enough to target various muscle groups, so you can maximize the effectiveness of your training and recovery sessions. This bundle includes four electrodes, with each electrode lasting approximately 15 to 20 sessions before requiring replacement. Consult the tech specs for a list of compatible EMS devices.