Sold a bunch of those big open end wrenches recently, including some CAT. Had a hard time getting postage and $5 apiece out of them. I screwed the 3-1/2" to my fence as a decoration, for $5 I'd rather have it on display than sell it. I've got a pile of Proto and MAC and Williams ones in the 1-1/4 to 2" range under one of my tool boxes, these are good combo's, not collectibles, haven't been able to sell for $25 apiece. Unfortunately, if you ship it ends up being in the $20 range each to ship individually, probably $10 each if you sell as a set. I had another lot of 3 of the equipment wrenches for sale, couldn't sell them for anything over the shipping so they're in the scrap iron bucket.
I got curious and weighed mine. 3 1/2" CAT open end. 12 1/2 lbs. Have another box end 3 1/2"; lighter weight for valves or such. 2 lbs 6 oz.