Lau Blower Wheel Part Number 01333701, DD9-8A. Preslok "DD" replacement wheels for direct drive blowers are dynamically balanced and forward curved, incorporating Preslok center disc construction for positive blade retention, providing higher RPM capacity and industry proven reliability. Wheels are made of cold rolled galvanized steel. Rotation is by the viewing center (hole) end. Specifications: Diameter 1/2" Rotation CW as viewing hole end. Convex Outside Diameter: 9-1/2 inches, Length: 8 inches. Number of Blades 43 See all pictures to see how the blades are curved and where the hole is.