Bonetto Cinturini 20mm Black Rubber Watch Strap Model 300D Made in Italy from high quality, vanilla-scented vulcanized nitrile NBR rubber (not silicone). Will not attract lint or dust Nitrile rubber is waterproof, non-toxic and non-allergenic; resistant to salt and UVA rays Bonetto Cinturini produces OEM rubber dive straps for many of the world's most famous watchmakers Fitted with an 18mm satin stainless steel deployant clasp with push buttons and polished steel safety lock To determine your strap size, measure the distance (in millimeters) between the lugs of your watch