This M42 mount 17-31mm focusing helicoid is designed for M42 42mm lens. It is very useful for macro photography
made with light-weight aluminum alloy
the length of this Helicoid tube 17mm (min) to 31mm (max), it offers a total of 14mm movement distance for lens focusing.
you may need an additional 39mm-42mm adapter if uou want to use 39mm enlarge lens with this Helicoid tube.
you may need an additional 39mm-42mm adapter if uou want to use 39mm enlarge lens with this Helicoid tube.