This is an authentic IWC Big Pilot’s dark brown calf leather watch strap. It was removed from an IWC Big Pilot 43mm watch and will fit other models with the same strap dimensions.
The strap is 21mm wide at the watch end and tapers to 18mm at the buckle end. The longer strap piece measures 14.5cm and the shorter piece measures 5.5cm. Batch number A59236 is stamped on the underside.
This item is in very good condition and I have given you clear images of this strap from every angle to help you see the quality before ordering.
If you are not sure if this will fit your watch or if you have any other questions, feel free to email me at Sales@TheWatchLink.co.uk. I'm happy to help!