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 and can be easily removed when not needed. This tube is useful for lenses without a focusing ring and can be used as a macro extension tube. There are no electronic elements in the adapter; aperture and focusing must be manually controlled. Color: Black Material: Aluminum alloy Made of anodized aluminum with a black finish and high-quality construction. The length of this helicoid tube ranges from 25mm (minimum) to 55mm (maximum), providing a total of 30mm of movement for precise lens focusing. Compatible with M42 screw mount lenses, including Carl Zeiss and Pentax 42mm screw mount lenses, as well as enlarger lenses. This helicoid tube is ideal for lenses without a focus ring, offering fine focus control for macro photography. The focusing helicoid tube features a 42mm front mount and a standard 42mm rear mount, constructed from lightweight alloy. It can be used as a macro barrel. Automatic diaphragm and autofocus functions will not operate when using this adapter. Manual focusing with A/M mode metering is supported. Compatible With: M42 Lens and Camera Package Includes: 1 x M42 to M42 Mount Lens Adjustable Focusing Helicoid Macro Tube Adapter - 25mm to 55mm Note: The package includes only the items listed above; other products are not included. Note: Lighting and display differences may cause slight variations in the color of the item shown in the picture compared to the actual product. Measurement error is +/- 1-3cm.