Kydex is a thermoforming plastic commonly used for knife sheaths. It is scratch-resistant, waterproof, and holds its shape well. We offer Kydex sheaths for a selection of pattern blades. Kydex sheath 410 fits pattern 41 blades, Kydex sheath 420 fits pattern 42 blades, Kydex sheath 440 fits patterns 39 and 44, and Kydex sheath 450 fits patterns 40 and 45. The black nylon folder pouch is useful for holding folding knives.