Eduard has released a series of WWII-era seatbelts in the “Superfabric” series. This review covers the following item:
The Superfabric seatbelts are made of some sort of “rubber-like” material. They have volume -i.e, they are not flat like decals- and they have a little bit of texture like if it they were made of ‘fabric’ (pun intended).
From what I read in the Eduard website you can either apply the seatbelts “dry” directly on the painted seatbelt or “wet” if the seatbelt has been coated in Future.