Overview & background
Whole peppercorns and salt taste best ground fresh, so the disposable-and-refillable glass grinder turned the spice bottle into a mill. The clear glass body is part of the pitch: you can see the peppercorns, judge how much is left, and the bottle looks good enough to stay on the table.
The category splits into one-trip 'grind and bin' grinders and premium refillable mills, but both use the same idea of a grinder mechanism threaded onto a glass body.
