I purchased two straps from Jim at OakLeafLeather at Etsy. The first was a baseball glove leather strap, and the second was a more substantial leather strap with some historic referencing to a P-51. I have two Fortis watches in need of new straps, and these seemed to fit the bill. I've had a very hard time finding a good strap for the black B-42 Fortis. Most of the leather straps I have tried were too thin and couldn't support the size and weight of the watch. Thicker straps wouldn't fit in the tight space between the lug and case. Each Fortis has a fairly narrow space between the case and lug, and Jim thinned the leather for me on the P-51 strap on the lug side so that there would be enough room for the strap. Jim was responsive, great to work with and the straps are extremely well made. The prices for the straps are excellent.
The baseball glove leather strap is fairly thin, and works well with the smaller Fortis. The P-51 strap is more substantial and stands up to the larger Fortis quite well. It's very comfortable and hugs my wrist without being too tight. I'm looking forward to seeing both of these break in more.
Here's a link to his store: https://www.etsy.com/shop/OakLeafLea...om_order_convo
Some pictures are below. Thought I'd share my experience. Has anyone else picked up any of his straps or leather goods?
The baseball glove leather strap:
The P-51 Strap with etching:
Thanks for looking.