Made of 304 polished stainless steel, the PS-1 model is designed for heavy duty jobs in 5-10 gal. (20-40 qt.) containers. It easily fits any 1/2″ electric chucked power tool.? The PS-1 model is designed for a max speed of 800 RPMS. Tools with 450-750 RPMS get the best rate of thorough mixing. MIxers can be permanently installed if desired.