When it works it works great and it's my favorite bit but the shape of the shaft is slightly different than those that came with my TR Industrial TR89105 jackhammer and will not activate the jackhammer unless I bang the hammer + bat into the ground with full force. more tiring and requires more effort than using a smaller chisel. It worked so badly my boss thought I screwed it up and bought us a different brand of bit as that bit would barely activate the jackhammer function and the shafts were so different. I would give it lower stars but it appears to be a well made drill bit and it was delivered on time but due to the difference in shank size to my other industrial TR bits it just doesn't work with the jackhammer model it is advertised for, and it sucks.