Ideal for commercial, educational and retail merchandising retrofits, White louver straight-blade cross-members for optimal light efficiency, Save 50% or more in energy over existing 4-lamp T12 luminaires, Fits troffers or parabolics as shallow as 3-1/2", Pre-assembled and wired to CEE-listed ballast, Ready-Set™ captive screws for quick, easy installation in 10 minutes, One-piece, tool-less reflector eliminates the need for parts bag, Reuse existing housing to lower installion time and removal cost