R61 "NATURE"- Genuine Buffalo Leather strap, with a Saddler's stitching (Hand stitched) cream white colour. When you purchase a RIOS1931 watch strap you are acquiring a high quality craft product. The combination of traditional , handcrafted perfection while constantly evolving has made the watch straps of RIOS1931 a unique, top quality product. R61 "NATURE" watch straps are available from 18 to 22mm, in black, dark brown, tan. Thickness of strap: (aprox) 6.0 mm to 5.0 mm. Cross Section: square. Select the size and colour that best suits your needs. Lug/Buckle Measurements: 18/18 mm, 20/18mm, 22/18mm.