The MM-2 includes a 6061 aluminum block frame with two 6" long steel rollers riding on SAE 841 oil impregnated bronze bushings. They use a superior grade of steel that is much harder than what is found on most comparable products and should last almost twice as long. The drive shaft, and all the axles are integral to the roller rather than screwed into the ends. This makes it fine to drive the mill clockwise, or counter-clockwise. All the axles are 3/8", with minimal freeplay in the bushings.
One of the knurled steel rollers is driven by a standard 3/8" electric drill (not included) to feed the grain through the adjustable gap and crush the grist. Both ends of the non-driven roller ride in bushings that are offset mounted in an adjustable knob. The knob is held in a fixed position by a set-screw that you can loosen to adjust the mill. This system provides an adjustment range of .070". Their knobs are made from 303 stainless steel for excellent durability, and are larger in diameter than the competition, as well as knurled for a positive grip. They also added a groove in their newest design knobs with a matching rounded head on the thumbscrew that allows for a much better grip on the knob to avoid gap changes while milling, and also providing knob retention.
If you don't purchase a base and hopper, you will need to fabricate one to feed the grist through the mill. The mill can be mounted above or below the base and attached using the included mounting bolts.