Review on 🌀 19mm - 127mm General Purpose PETUOL Mandrels by Charles Barney

These are not the hole saws you expect. They are not true at all. BUT! They're cheap and I wasn't trying to spend a fortune on plastic. They have an aggressive bit and cut thin plastic perfectly in reverse. I use them to make holes in my mesh cup hydroponic buckets. To be honest I wouldn't use them on anything but plastic. It looks like they used mild steel for this product and I have a feeling you'll bend or break something if you try to go through hard wood or metal. When cutting through thick acrylic I would recommend running the hole saws forward and as you approach the bottom edge switch to reverse to eliminate the kick and get a nice clean cut. Hope that helps!