Robert Wilhelm incorporates his highly functional mechanism (quality stainless steel and non-corroding materials) into all of his unique and artful crushers. To fill, unscrew the knob and remove the top. Fill with salt crystals or peppercorns and replace top. Replace the knob and tighten until snug. The tighter the knob, the coarser the grind. We have 3 versions of the Alpha Grinder.