I just got these today at home depot and had the first one out of the pack explode while cutting a leaf spring. Good thing I had my shield on, one of the pieces shown hit above where the shield mounts just above my forehead. The wheels are 4-1/2" cut offs for an angle grinder. Not sure if the wheel was defective but I won't use any more out of this pack or buy any more of that brand. They will go back tomorrow. I thought I'd share this experience. I ended up using my muffler cut off tool.