Prime-Line Products G 3119 Sliding Window Roller Assembly, 1/2 in., Brass, FLAT Edge Rollers (Pack of 2) Used to replace damaged or missing roller assemblies on horizontal sliding windows 1/2 in. outside diameter of wheel. Overall net outside dimensions of housing are: 1-1/2 in. wide x 1/2 in. deep x 1/2 in. tall White housing Brass wheels in plastic housing