Sportsheets Harness Compatible Rubber Various Sized O Rings Set of 4, perfect to use as either cock rings in their own right or as ideal accessory to allow you to use a wide variety of dildo sizes with your favourite strap on harness. The set consists of one of each of the following sized rings: 2” 1.75” 1.5” 1.25”. Will accommodate most dildos with a flared or even suction cup base. Firm Nitrile 70 (NBR) rubber (latex free) with minimum amount of flexibility. They are interchangeable to fit in most of your favourite Sportsheets harnesses.