Advanced universal compatibility product mat Reusable electrodes can be sealed;20 electrode pads are universal Perfect replacement electrode for massage or electromuscular therapy. Often used for people with vascular or musculoskeletal disorders, or for people with high levels of physical activity every day, such as athletes. Provide self-adhesive replacement electrode pads to ensure that electrical stimulation can work properly in every event. colour: black + white Material: electrodes size: 4cm Package Contents: 20 x Pad round electrode Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.