An Optional velcro strap in black or gray was available – these straps hooked up to the main male connection with the bracelet. Luckily for us, the fabric strap in the IW3715-36 and the alternate rubber strap in the IW3548 suit the Aquatimer! , Rolex. Constantly a reputation to reckon https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/