These 25 round blocks are half-size blocks that are excellent for small batches of cases. These blocks are also commonly used on the shooting bench to hold loaded rounds or fired cases. blocks are machined from solid white polyethylene providing the reloader with a very durable, easy to clean loading block. Each block is machined to fit the specific cases you reload and has finger grooves machined into the sides to provide a sure grip. Each hole has a slight chamfer for easy case head entry. The "Poly" blocks are dishwasher safe for easy cleaning. We use white polyethylene because spilled powder shows up easily. These blocks are 3/4" thick to provide deeper holes for Mfg: Sinclair International