Not sure what this actually is, but we did have four of them and used them as tool boxes, we are still using one.
They are 3 foot 6 inch 'ish' long, about 18 inch wide and about 15 inch deep.
Made out of heavy steel about a 1/16 in thickness. Fully flanged and rivetted (like a firebox!), and are thus very period. Properly forged fittings and the like.
Would be just the thing to mount on the front of a watercart or suchlike to keep your bits and pieces in, perfectly 'period' to boot. A stout padlock would also keep the pikeys out.
It wants a little TLC, there are a few missing rivetts and there are some stress cracks in the lid, (see pictures) but nothing that isn't a simple fix.
£120 ono