Made of PP plastic, sturdy and durable, smooth surface, not easy to break.Suitable for hexagonal nuts, easy to install and disassemble. It can provide good protection for your nuts and is a good tool to prevent them from rusting and corrosion. Extend the service life of bolts.Specification:Material: PP PlasticFit Nut Size: M6Hex Socket Width: 10mm / 0.39"Total Size: 14 x 14mm / 0.55" x 0.55"(OD*H)Package Content: 50pcs x Nut Protection Cap Covers