This Benro 82-67mm step down ring is designed for use with the Benro FH100 filter holder. In combination with a separately available 82mm adapter ring it will allow you to attach your filter holder to lenses with a 67mm diameter screw thread mount. The FH100 holder is sold separately.
The FH100 Filter Holder attaches to your lens with an adapter ring, available separately in sizes from 72mm to 95mm. To attach the filter holder on lenses with filter threads sized 72mm and smaller use a Benro stepping ring such as this one. Stepping rings are available in numerous sizes, and are used in combination with an adapter ring.