UNIVERSAL COMPATIBILITY - Our TENS model pads are designed to fit your muscle stimulation machine with pigtail snap connectors sized 1.8 - 2.5mm. REUSABLE - This bulk pack of TENS electrodes can be used multiple times for optimal relief from discomfort. Simply use the resealable package to keep your pads fresh and clean. SELF-ADHESIVE - These adhesive pads for TENS unit have a high quality surface gel to ensure a strong and comfortable hold on your skin. Affix to your arm, leg, back, chest or shoulder with ease!