The UL electrical mounting block is designed to mount light fixtures. Includes electrical box and mounting block. Manufactured with ultraviolet-stabilized color, minimizing the effects of exposure to the elements. Compatible with all siding profiles. Rich textured appearance. Surface dimensions: 7-1/8" x 7-1/8". Flange dimensions: 7-11/16" x 8-1/2". Siding receiver: 5/8" - 1" in 1/8" increments. Color: White. No. EBLOCK PW: Surface Dimensions: 4-7/8" x 5-7/8", Flange Dimensions: 7-1/8" x 8-1/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: White