This is a 63 adapter ring for the Hasselblad bellows hood. (For the first model where the rail doesn't fold) This ring is used when attaching the bellows hood to the SWC, C50, or 60mm lens. (It can hold a 63 filter) It's a rather old accessory, but it's in good condition. If anyone is looking for one, how about it? Instant purchase is OK. No price negotiations. Please refrain from purchasing if you are overly concerned about minor details. I am listing various Hassel items. #Hasselblad #Hassel #HASSELBLAD