Just ordered some custom straps from @msbespoke_ on Instagram for my IWC 3881-01, and I gotta say, his workmanship is excellent. Nice supple calf leather strap, in a similar design to the original IWC pilot straps.
The navy blue is slightly lighter than the original, but I think it suits the watch perfectly. Here are some pictures of the beautiful French stitching. Cost me RM280 shipped in the Klang Valley.

