Description M42 to M42 Mount Lens Adjustable Focusing Helicoid Macro Tube Adapter - 25mm to 55mm The all-metal adapter is designed to fit the lens securely, yet can still be removed when not needed. Introduction: This tube useful for lens without focusing ring. And it can be use as macro extension tube. There is no electronic in the adapter. and focusing must be manually control. Colour: Black Material: aluminum alloy Made of Anodized Aluminum in Black finish with high quality. The length of this Helicoid tube is 25mm (min) to 55mm (max),it offers a of 30mm movement distance for the lens focusing. You can use M42 screw mount lenses, such as or 42mm screw mount lenses, and even enlarger lenses. This Helicoid tube is useful for those lenses without focus ring, Tube offers fine focus control for macro photography. This focusing helicoid tube is made with 42mm front mount and standard 42mm rear mount and is made with light-weight alloy. It could be used as Macro Barrel. Automatic diaphragm, auto-focusing will not operate correctly while using this adapter. Manual focusing with mode metering is ok with the adapter. Compatible With: M42 Lens Camera Package Include: 1 X M42 to M42 Mount Lens Adjustable Focusing Helicoid Macro Tube Adapter - 25mm to 55mm 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.