The IWC Aquatimer 3536 was introduced in 1998 as the dive watch of the sporty GST collection. It marked the return of the Aquatimer name, which IWC had first used for its divers watches in the late sixties. The 3536 featured a case of 42mm in either titanium or stainless steel with an external revolving bezel. It is paired with an integrated bracelet or an optional velcro strap, although rubber straps of the later generation also fit.
Reference IW3536-01 is done in full titanium.
The reference for the velcro strap with titanium lugs is A04920.