Great bit set for masonry work. I've used this with a concrete/masonry bit and with a regular tile bit setting. I dip them in water to keep them cool for longer use. And before I put them away, I clean and oil them with a 3-in-1 multipurpose oil. So far I haven't had any problems with this set. One star deducted because of the packaging. It comes in a sealed plastic package and can be difficult to reuse if handled improperly. I used a razor to cut the top front of the plastic to create a valve that can be used to insert into the inner valve on the back of the packaging (see pictures).