This is a great little power engraver. Like most in this category, it's air cooled internally, so you will always hear a little air going through inside when it's running. It works well and doesn't leak. I'd recommend another regulator between this and the compressor just to ensure that you don't hit this thing with more PSI than you should have (I think around 40-45 PSI is what this is expecting and what the handpieces can handle as a maximum). It comes with a filter in the mix, but you could buy a regulator/filter and bypass the one it comes with if you want to.
The handpiece chucks don't quite fit 1/8" standard gravers, common here in the US from a variety of jewellery tool companies, so I had to take the chucks and drill them out to 1/8". It was easy and quick, and now I can use a variety of carbide gravers and standard HSS gravers. You slide the graver in and tighten a grub screw (set screw) to hold onto things. The handpieces leak air (only a tiny amount) but this is NORMAL. It's common in all of these, and it's just the way they're designed. Since the air has to go to the handpiece to move it, the excess has to go SOMEwhere, so it's designed to leak out the handpiece. One of my handpieces leaks a little more than the other, but not enough to really notice a difference in usability.
I use an 8 gallon quiet compressor with this, and it kicks in relatively often. My compressor is designed to kick on at 90PSI and shut off at 120PSI, so it kicks on maybe every 4-5 minutes. If I had a larger compressor, it would kick on less often. If I had it set to kick on at a lower PSI, it would kick on less often. But it's a CAT compressor, and really very quiet as compressors go, so it's not a nuisance. I barely even pay attention when it kicks on and off. My shop exhaust fan is much louder.
This uses 6mm OD tubing. It will TAKE 1/4" OD tubing without much in the way of issues, but you should really use 6mm if you can find it. It's cheap online from a variety of places. It does not come with enough 6mm tubing to do much more than connect the foot pedal to the main box. Connecting your compressor to the air filter and the air filter to the main box means you're going to need more tubing of your own.
Controls are standard. There's a switch to switch between handpiece 1 and handpiece 2 (it comes with TWO handpieces, which is crazy for this price, but great). And then there's an 'auxillary' connection that's designed for other kinds of tools that require air. There's a 'bias' dial, which controls the starting point of the foot pedal. The bias knob should be closed when you're adjusting the machine.There's a primary air pressure knob (good for different kinds of handpieces and controlling how strong you want the pressure to be, dependent on what the handpiece will take (they're all different)). And there's a speed control knob.
A FANTASTIC engraver!
Donna Voelker 
