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". No. MBLOCKR PW: Surface Dimensions: 5-1/4" x 7", Flange Dimensions: 5-7/8" x 7-1/2", Rectangular Knockout: 2-1/4" x 3-7/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: White No. MBLOCKR PA: Surface Dimensions: 5-1/4" x 7", Flange Dimensions: 5-7/8" x 7-1/2", Rectangular Knockout: 2-1/4" x 3-7/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: Almond No. MBLOCKR EQ: Surface Dimensions: 5-1/4" x 7", Flange Dimensions: 5-7/8" x 7-1/2", Rectangular Knockout: 2-1/4" x 3-7/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: Gray No. MBLOCKR PC: Surface Dimensions: 5-1/4" x 7", Flange Dimensions: 5-7/8" x 7-1/2", Rectangular Knockout: 2-1/4" x 3-7/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: Clay No. MBLOCKR A7: Surface Dimensions: 5-1/4" x 7", Flange Dimensions: 5-7/8" x 7-1/2", Rectangular Knockout: 2-1/4" x 3-7/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: Tan No. MBLOCKR PB: Surface Dimensions: 5-1/4" x 7", Flange Dimensions: 5-7/8" x 7-1/2", Rectangular Knockout: 2-1/4" x 3-7/8", J-Channel Inside Dimensions: 3/4" adjusts to 1-1/4", Material: Vinyl, Color: Cream