Stamo mixers from Kruger USA are available in typical round, solid shafts or square, hollow shafts for deeper tank applications. These square shafts are constructed of structural carbon steel and cladded with stainless steel (304 or 316), providing increased fatigue life and tensile strength. With less hanging weight per foot of length, square hollow shafts require less power to operate, offer lower installation costs, and allow for single-piece shafts to be used. 919/677-8310; www.veoliawatertech.com.