Rimba Electro Play self adhesive gel pads with a size of 40 x 40 mm each. This package contains 4 single, uni polar pads.These pads are flexible and can be used 10 up to 15 times depending how clean the gel stays. A clean, hairfree skin makes the best contact. An individual pad is unipolair so you need to use 2 pieces or one pad and an other uni polar device to create an electric shock. Always be careful, do not use if skin is broken or iritated, when you have heart problems or are pregnant.