This radial flow impeller is a popular choice for high speed, low viscosity mixing in carboys or narrow neck flasks. The blades are pinned to an 5/16 inch (8 mm) diameter shaft, fanning out with agitation to a maximum diameter of 3 ½ inch (90 mm). Blades and shaft are electropolished 316L stainless steel. A high shear impeller with moderate vortexing properties, creating a vortex in 19 L (5 gal) of water at 1000 rpm.