Twist mills from William Bounds come in a variety of sizes and materials. All offer lots of grinding power thanks to a unique grinding mechanism that works in both directions. So, you get more salt or pepper with fewer turns of the handle. The acrylic Twist mills are easily adjustable for three degrees of coarseness. The pepper grinders employ a steel mechanism, the salt grinders are ceramic to withstand the corrosive nature of salt. Both come with a lifetime guarantee on the mechanism.