I use a Weathertech mat ON TOP of the Ruff Rug cargo liner. Agree their material is thick but I haul other things around and already owned it. Wouldn’t need it if it was just my dog. The custom liners tend to be more expensive but definitely worth the price.
I like the cost of Canvasback and the material of Ultimate Pet Liner and eventually tried the Ruff Rug 4runner cargo liner. Made to fit the floor and made with the same vinyl waterproof material:
ruffrug.com/products/toyota-4runner-cargo-liner
They have optional sides as well.
Have tried a few custom liners in the past and literally just bought one from Ruff Rugs for my newish 4runner a few months ago: Toyota 4Runner Cargo Liner
I have a large lab and they tend to rip up the interior. He goes everywhere with me and sheds a ton (especially during summer). The Ruff...