6x6 to 4x4 reducing board. Looks like nickel hardware, knobs screw down. Appears to be a professionally made device and is very sturdy. It fits my camera that uses 2D type boards, but I no longer have any of my 4x4 boards, so don't need it.
The interior corners are at right angles and not rounded, so probably wouldn't work for a Deardorff.
Price: No real idea. One on Ebay is $135 and I've seen them here for $75. How about: $50+ $5 USPS priority shipping? Paypal ok, but USPS money order preferred, especially by my dog who gets treats from the bank tellers. Reasonable offers, trades, etc considered. $ to apug if sold here