Are best for greenhouse type glass. I have managed to 3/4 reglaze my newly moved greenhouse without having to cut any glass. Nor, I might add, losing a single solitary pingfuckit in the process which is quite an achievement in itself but the last bits need me to do glass cutting. Which, incidentally, I have never done before in my whole life so in the process I shall be adding a new skill to the list. It'll be the 1.5kw Angle Grinder not the toy by the way.