You probably got that from one of my posts. I have been using those for years. They are the most ridgid cheap plastic box I have found, and they have a rubber gasket. You can put 200+ pounds of man meat on there and it won't flex like others such as action packers. However $50 is too steep. I got mine for around $25 on sale. I know that Storables sells them for around $40. I would actually pay $40 for one. You have to trim the little outside "wing tabs" a bit under the outside of the lid with an angle grinder/cutter to get them to sit lower in a frame bay, but they are easy to cut off. I was just actually outside an hour ago packing one of these up with the Kni-co packer wood stove for a steelhead fishing trip down the Grande Ronde this week. Just sewed a Ti-Goat stove jack in my MSR Twin Brother so I can use the wood stove in there for winter steelhead multiday trips to the land of frost.
about 235 pounds of man meat on a Clavey flip seat bracket over the top of one of these boxes in the attached pics
and 195 pounds of man meat in the rower position for the way overloaded SDP