9 - 11 Double Inlet features a new design ensuring more precise blade spacing and improved consistency in alignment and balance. Dynamically balanced, forward curved. Incorporates Preslok center disc construction for positive blade retention. Provides higher RPM capability and industry proven reliability. Offering the same outstanding features and high quality as Lau A Series Preslok Wheels, DD Preslok Wheels have a special hub for use with direct drive blowers. All Standard Replacement Wheels are galvanized, cold-rolled steel Standard center disc arrangements shown