You are bidding on a bag of 20 O ring seals to fit standard garden hose connectors,  Hoselock, Gardena etc including all brass fittings as well as they are all this standard size.  These are SILICONE RUBBER which are the best at resisting sunlight which is the main reason these seals fail prematurely in the first place.Most seals sold for this purpose are made of Nitrile rubber which will fail in the first year if subjected to sunlight.  They are a slightly softer grade of rubber and seal better than the standard black ones.