Review on Amazon Basics Rubber Sanding Block: Essential Tool for Smoother Surfaces by Bret Wong

A slightly different version of the standard rubber sanding pad. Like its predecessors, this pad holds 1/4 sheet of standard sandpaper. It has three main differences from older versions.1. The block is made of rubber on the outside and hard plastic on the inside. This will make the "flaps" that hold the sandpaper a little stiffer, making it easier to load the sandpaper onto the block.2. The valve hinges are also made of hard plastic. Time will tell but I think they hold up better than the old rubber straps.3. The bottom of the block is covered with a grid of holes. In theory, for the same user pressure, this should put more pressure on the crosshatch area of the sandpaper, resulting in faster stock removal. Unfortunately, the casting process left a lot of burrs around the holes. This creates lumps under the sandpaper, resulting in a very uneven sanding. Unfortunately, this makes the sharpening block virtually useless for all but the coarsest of sharpening jobs unless you spend a lot of time deburring the knife.