Surface: Genuine VEG Cowhide Skin. 26mm, 25mm, 24mm, 23mm, 22mm, 21mm, 20mm, 19mm, 18mm, 17mm, 16mm, 15mm, 14mm. - Inside: Genuine Cowhide Skin. Note: With Buckle sizes 22mm and 24mm, the hole on the strap will be oval 4mm-2mm.