These elecro Cock Rings are designed to go around the cock and balls, just like a regular cock ring. Not only will it help maintain a strong erection but each ring has two metallic conducting strips that will create an intense sensation when equipped with an electro power unit. It can also be used around the ball sack. Made of a clear acrylic. Works with the Folsom and Eros Tek banana leads. Comes in 2 sizes: Medium has a 1.75 inch diameter opening. Large has a 2 inch opening. The large fits 80% of men. For the Rimba or Tens kit you'll need the Pin to Banana Inline Adapters.