Lock Ring for Sony FE 600mm f/4 GM OSS lens.

A lock ring is included with every lens hood order if required by the lens hood.
Lock Ring for Sony FE 600mm f/4 GM OSS lens. Compatible with Zemlin Photo HZ-S158 & HZ-160 Series Hoods. Approximate weight: 42g. Order only as a replacement or if using a hood on multiple lenses.
Photo shows a Canon lens which takes a similar lock ring.