I am selling a pair of Marquipt Single Fender Holders for $300.00. These are the style that bolt through stanchions or similar surface. ID is 11.5" and depth is 20" - according to Marquipt these are intended for 10" diameter fenders. Great condition, they came off my boat which has always been in the Great Lakes & Upper Chesapeake, so no noticeable corrosion. Located in Toronto, ON but I am willing to ship at purchaser's cost.
I only have the pair, but I did notice that another pair are for sale on eBay from a Florida based seller. Based on the description they appear to be the same size as the ones I am selling (11.75" ID intended for 10" fenders).