This is a Nikon F-mount macro reverse ring. It is in reasonably good condition. Immediate purchase OK, no price negotiation. This ring allows you to attach a lens with a 52mm filter thread in reverse to the camera body, either directly or via a bellows attachment. ● For magnifications of 1:1 or greater, performance is improved by mounting the lens in reverse. ● The BR-2A is for lenses with a 52mm filter thread, and the BR-5 is for lenses with a 62mm filter thread (used in conjunction with the BR-2A). * Cannot be used with G or E type lenses, or PC lenses.