This is an extension kit that works with Grizzly "Bear Crawl" mobile bases and mostly used with table saws. It provides support for your extension table so the whole saw and extension table can be moved at once. Capacity is 400 lb. Be sure to check the Grizzly site to see which bases this is compatible with.
I bought this for use with another tool and it didn't work out. It is new and in the box. Check it out; these are about a hundred bucks online.
Located North of New Meadows but I get down to Boise / Meridian about monthly and can bring this down if you are flexible on time/date and meeting location.