The Caframo Collapsible Blade Impeller features a 3.5" diameter, and is pinned to a 5/16" by 16" shaft

The impeller will vortex 5 gallons of water at 100rpm. Radial flow.

Composed of 316L electropolished stainless steel, it offers high shear for mixing in carboys or narrow neck flasks, and will fit into an opening greater than 0.4".