"Finding discs for 125mm grinders is not so easy. Especially when you want the thin slotting discs. The extra 10mm makes a big difference to the depth of metal you can cut and the speed of cut. These disks seemed to fit the bill, but they are multi-purpose. I was using them for mild steel and they don't last long at all - they practically disappear in front of your eyes. Its a little unfair I know, but steel only disks last about 5 times longer."