That storage box looks interesting; my thoughts:
-the box weighs just about 60 LBS (about the weight of an extra battery);
-several truck campers make tubs that are step-constructed geometry to fit tightly over the truck bed wheel wells and take up all the space aft of them (like ours), so study your truck camper tub design carefully before buying one;
There must be a blow-molded HDPE storage box alternative out there on the market that would be about 1/3rd the weight of this metal box (this would be a good product for someone like TorkLift to design/offer, possibly: blow-molded fore/aft truck camper side saddle storage boxes, for the most popular truck campers' tub geometries)? For our camper tub design, I wish an HDPE bed-mountable box that would fit fore of our 2 wheel- wells were available (to mount, securely, 2 more batteries).
Thanks for posting the link. This product offers much food for thought as additional storage!