This. But if you are not a professional carpenter like me, I suggest looking for other options for your carpentry. There was no guide for this beat so google it. It took me forever to set it up. I recommend buying beats that come with pre-made blocks or making your own once you understand how they work. The box states that the overall cutting height is 13/64. I think it's wrong. The preferred thickness of your work piece should be 1/2 inch or more. You cannot use it on thinner woods. Initially, the cutting edges of the drill were very sharp. feels spicy and the wood has burn marks. You can get the sides in one go, but you'll need multiple passes for the front, which is time-consuming. I was able to line up the joints perfectly, but the two pieces don't really connect like a tongue and groove joint (so why call it a lock bat?!) Bottom line: if you're a carpenter who needs this bit all the time, go for it . This allows you to make clean connections. some and some nail and glue. If you're just buying this for a small project I suggest looking at other options.