These straps are handmade from Horween shell cordovan. Three colours are available, whisky, Horween No. 4 Oxblood, and Horween No. 8 (a burgundy-brown that is probably Horween's most famous shade). All straps have ivory stitching. These bands will acquire a beautiful patina over time.
For a bit of background, I am a watch collector and also a fan of well made men's shoes. I wanted shell cordovan straps for my Panerai since I have some pairs of shoes in the same material. I found these straps which I think are both excellent quality and a good value proposition.
Shell cordovan is a leather obtained from the rear of a horse, prized for its toughness and colour. Horween is one of the few tanneries in the world still making shell cordovan, and they supply shell cordovan to most of the high-end shoemakers who use the material, like Alden and Crockett & Jones for instance.
The dimensions of the straps are as follows:
Lug and buckle width: 24 and 22 mm
Length: 76/116 mm
Thickness: 4 mm tapered to 3.5 mm
All straps are fitted with a brushed steel buckle affixed with a spring bar. Each strap is US$128 including shipping worldwide. If you'd like the strap without the buckle it's US$118 shipped. PayPal payments are gladly accepted. I can be reached at rsgcap@gmail.com.