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.