Of the power tools I own, this diminutive Makita impact driver is one of my favorites. I recently had to install a Murphy Bed and this thing drove lag screws into the subfloor like I was hammering brad nails. As someone who cut his teeth with bulky, cordless, keyed-chuck power drills with no hammering action, that something this small could pack so much punch has always amazed me.
I always pictured a powerful little leprechaun inside making the magic happen; but as it turns out, the impact mechanism's a bit more prosaic. Nick Moore, whose YouTube channel is dedicated to sharing "Science on a budget, [to] take a closer look at the world we live in," cut the housing away on an impact driver extension to show you how it works. Pretty cool: