MBLOCKR A4 STERLING GRAY A4/06 VNYL REC J-BLOCK | The split recessed J-Block mounting block has a patented hinge that allows for ease of installation without removal of electrical receptacles and water faucets. Manufactured with ultraviolet-stabilized color, minimizing the effects of exposure to the elements. Compatible with all siding profiles. Rich textured appearance. Surface dimensions: 5-1/4" x 7". Flange dimensions: 5-7/8" x 7-1/2". J-Channel internal dimension: 3/4" adjusts to 1-1/4". Knockouts: Rectangle 2-1/4" x 3-7/8". Limited lifetime warranty