Given a recent question about impact use and warranty, which was answered by the manufacturer, I decided to edit this review and make an important point ahead of my review proper. I have the 61 piece security bit set made of S2 steel. S2 steel is used to make striking and struck tools. It can get very strong, handling torque well, and very hard, standing up to repeated use. These bits, however, are not chisels or punches. They are not impact rated and probably are not meant to be used with cordlSee full review