This is a mount adapter for attaching Hasselblad lenses to a Pentax 645 body. It's made by combining parts from a Hasselblad intermediate ring and a Pentax 645 lens mount, so both sides are genuine mount specifications. I recall it was made by a manufacturer in the Kansai region, but it seems they are no longer in production. Unlike many mount adapters, there's no rotational play, so the stability when turning the focus ring is as good as using genuine parts. I'm selling some of my mount adapters because I have too many. Please note that this adapter requires stop-down metering. The precision is excellent, providing sharp resolution from the widest aperture. The appearance is like a genuine part, so it looks good without any noticeable difference. (I've also included images of it mounted on a 645Z for reference.) Instant purchase is okay. Negotiations for price reduction and requests from overly sensitive buyers will be declined. Thank you for your cooperation in a smooth transaction.