Description This M42 to RMS adapter is made of premium material, which can withstand long-lasting use. Features the aluminum alloy material, which has high durability, not easy to deform. Fine workmanship, practicality. Features -Color: Black -Material: aluminum alloy -Size: 4.00X4.00X0.40cm/1.57X1.57X0.16in Outer diameter: 4cm Inner diameter: 2cm - Allowing your M42 interface camera to connect with RMS interface objective lens. - Bringing more versatility to your camera photography with this adapter ring. - Replace your old or broken camera adapter ring with a new one. - Easy to install and detach to provide more convenience during . - Special design and it is in fine craftsmanship. It is the best replacement for your old, broken one. Allowing your M42 interface camera to connect with RMS interface objective lens. Bringing more versatility to your camera photography with this adapter ring. Replace your old or broken camera adapter ring with a new one. Easy to install and detach to provide more convenience during . Special design and it is in fine craftsmanship. It is the best replacement for your old, broken one.