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 components in the adapter; aperture and focus must be controlled manually. Color: Black Material: Aluminum alloy Made of anodized aluminum with a black finish. The helicoid tube length adjusts from 25mm (minimum) to 55mm (maximum), providing 30mm of focusing travel. Compatible with M42 screw-mount lenses, including Carl Zeiss and Pentax 42mm screw-mount lenses, as well as enlarger lenses. This helicoid tube provides precise focusing control for macro photography, especially for lenses without a focus ring. Features a 42mm front mount and a standard 42mm rear mount, constructed from lightweight aluminum alloy. Can be used as a macro barrel. Automatic diaphragm and autofocus functions will not operate while using this adapter. Manual focusing with A/M mode metering is supported. Compatible with M42 lenses and cameras. Package includes: 1 x M42 to M42 Mount Lens Adjustable Focusing Helicoid Macro Tube Adapter – 25mm to 55mm