colour:Black Cap: 1. Body cap for M42 mount camera body / mount adapter 2. Rear lens cap for M42 mount lens Type: screw in new and unused material:metal adapter: You can use M42 screw mount lenses, such as or 42mm screw mount lenses, and even enlarger lenses. It could be used as Macro Barrel. Instruction:Attach the Helicoid tube to the lens,then mount the combination of lens and Helicoid tube to the camera. This listing is for Adjustable Focausing Helicoid M42 to M42 12mm-17mm lens adapter. Automatic diaphragm, auto-focusing will not operate correctly while using this adapter.Manual focusing with mode metering is ok with the adapter. Material: Aluminum alloy Package Contents: 1 x Body Cap 1 x Lens Rear Cap 1 x adapter Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Made of Anodized Aluminum in Black with high quality. The length of this tube is 12mm(min) to 17mm(max),it offers a total of 5mm movement distance for the lens focusing. 2 pcs Lens Cap & 1 pcs Adapter This tube is useful for those lenses without focus ring offers fine focus control for macro photography. This focusing helicoid tube is made with standard M42 mount and is made with light-weight alloy.