is a great tool and hits hard. but the bit receiver was not handled properly. I had to grind all 4 bits to get them to slide properly. In addition, all bits have a notch on the back so that they are at a 90-degree angle to the handle when inserted. Look at the photos in their ad and you can clearly see the lock is on the side but the bits are notched in the front. why they would sell a defective product is beyond me. My solution was to remove the bottom of the hammer and rotate it. The bits are still not straight, but close enough for the tool to use. some people tried to carve a new score - too much work. I love this tool but am very disappointed that the company even offered to sell bits that don't fit but after waiting 3 weeks for them to arrive I didn't want to send them back - I think they are. expect further. So far it's a great tool, but I wouldn't recommend it to anyone who doesn't have the skills to overcome all the problems that come with it. good luck if you buy one.