5KU ZENIT A-1 Style Sling Mount BK

・Material: Aluminum alloy
・Product dimensions: Total length approx. 27mm, total width approx. 49mm, total height approx. 10mm
・Body weight: Approx. 19g
・Package size: 120mm x 10mm x 100mm
・Total weight (package included): Approx. 28g
・Compatible manufacturers and models: Models with a 20mm rail that can be installed while sliding

This is a Russian Zenit A-1 (А-1) type sling mount.
Remove the hexagonal screw at the bottom, slide it onto the 20mm rail, and retighten the screw.