An Optional velcro strap in black or grey was provided – these straps attached to the primary male link of the bracelet. Fortunately, The material strap from your IW3715-36 and also the alternate rubber strap in the IW3548 in shape the Aquatimer! Christie’s This was largely a ref. 6538 — https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/