Description: 1.Each metal cap set include 1 pc lens rear cap and 1 pc camera cap 2.Protect your lens and camera from dust, water and other damage 3.They are made of metal, which is wear-resistant and durable 4.M39 is for LTM LSM Leica Screw Mount 39mm 5.M42 is for LTM LSM Leica Screw Mount 42mm Material: Metal Color: Black, Silver Size Available: Black M39, Black M42 Package included: 5sets X Metal Cap