This tube is suitable for lenses without a focus ring. It can be used as a macro extension ring. There are no electronics in the adapter, and aperture and focus must be controlled manually.

Specification:
Front Mount: M52 Screw Mount Female (M52 x 1mm)
Rear: M52 screw mounting male (M52 x 1mm)
Length: 17mm to 31mm (14mm travel distance for focusing)
Focus: Manual
Material: aluminum alloy
Package includes:
1 x focusing spiral
Brand new and unused