"after buying a very cheap disc which was a waste of time i bought this as it was a reasonable price and the spec seemed to be what i required. the discs are not the best on the market but for the price you cant really go wrong. i used these to rake out mortar joints prior to repointing. they lasted reasonably well although when you get through about 3/4 of the dimond edge the last 1/4 wears out very quickly. i can however recommend these if it is being used on generally softer materials."