As soon as we started using it, we were very satisfied with very strong power (compressor pressure naturally within regulation) as in other reviews, but the attached spring broke in just 1 hour. Although I spared another pair of springs that I had bought in spare, I used it and used it, but this time the attached chisel collapsed considerably earlier than the thing I normally use (100 or less) In addition, I use it the next day When trying to do, the chisel does not vibrate due to air leakage from inside (?) This time. . . I bought two pairs as they jumped to the low price but it is very disappointing that it will not be usable in just 2 days. From next time I think I will buy things of firm making even if it is expensive.