Leather sheaths have been around for ages and usage is pretty self-explanatory. Kydex is a relatively new material, stronger and more water-resistant than leather. It doesn't rot or mold and you don't usually need a strap to retain the blade. Because of the extra durability and tight custom fit, drawing and sheathing in Kydex is done a little differently. Here are a few tips and tricks to make the most of your custom Kydex sheath. DRAWING A KNIFE FROM A KYDEX SHEATH.