An Optional velcro strap in black or gray was offered – these straps connected to the primary male website link of the bracelet. Fortunately, the fabric strap in the IW3715-36 as well as alternate rubber strap from your IW3548 fit the Aquatimer! Christie’s This was largely a ref. 6538 — https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/