This is an easy-to-use bolo-style cock ring, made from silicone and ABS plastic. The smooth and stretchy silicone ring is adjusted by pressing a button on the round ABS plastic keeper and sliding to desired tightness.  Once the button is released, the ring stays put.

The ends of the silicone ring are capped in ABS plastic stoppers, so that you don't accidentally pull the ring out completely from the keeper during removal or adjustment.  This ring is simple at a great price.