Just wanted to share something I have been doing for years. I use a 4' X 6' 3/4 " thick rubber matt that I purchased at a farm and ranch supply that is sold primarily as a horse trailer/stall floor pad. They sell for about $35 and fit between the wheel wells with about an inch on each side. It is great for real heavy duty use like throwing 4 x 4 fence posts, 4" drill pipe etc w/o denting the bed. I have used a standard 1/4" matt before and large objects will dent the bed through it. I have a spray in liner with the horse stall pad on top of that. It weighs about 65 lbs. It doesn't cover the corners in front and behind the wheel wells but that usually isn't where it is needed. It has texture and is soft so it grips loads real well....cheers

My next door neighbor was checking out my new truck today and he recommended the exact same concept.They have horses and thats what he uses for his c/c on top of the spray in liner.