A radial flow PTFE impeller for high speed, low viscosity mixing in narrow neck flasks. The blades are attached to an 5/16 inch (8 mm) diameter PTFE-coated shaft, fanning out with agitation to a maximum diameter of 1 ⁹⁄₁₆ inch (40 mm). The stainless steel core of the shaft provides stability. PTFE (polytetrafluoroethylene) can be used under the most adverse conditions. This high performance coating is insoluble, non-contaminating and has exceptional thermal resistance. It is easy to clean, does not scratch other surfaces and is unbreakable.