M42 to M42 Mount Lens Adjustable Focusing Helicoid Macro Tube Adapter - 25mm to 55mmThe all-metal adapter is designed to fit the lens securely, yet can still be removed easily when not needed.Introduction:This tube useful Compatible With lens without focusing ring. And it can be use as macro extension tube. There is no electronic elements in the adapter. aperture and focusing must be manually control.Colour: BlackMaterial: aluminum alloyMade of Anodized Aluminum in Black finish with high quality.The length of this Helicoid tube is 25mm (min) to 55mm (max),it offers a total of 30mm movement distance Compatible With the lens focusing.You can use M42 screw mount lenses, such as Carl Zeiss or Pentax 42mm screw mount lenses, and even enlarger lenses.This Helicoid tube is useful Compatible With those lenses without focus ring, Tube offers fine focus control Compatible With 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 A/M mode metering is ok with the adapter.Compatible With:M42 Lens CameraPackage Include:1 X M42 to M42 Mount Lens Adjustable Focusing Helicoid Macro Tube Adapter - 25mm to 55mmOnly the above package content, other products are not included.Note: Light shooting 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.