The Hinge Kits are very user freindly, just slip it on your existing elbow and secure with screws (provided) then slide your existing extension on the kit and you have a flip-up.
Available in "A" or B style, 2x3 and 3x4.
Colors.

Hinge Kits

Sort by:     SKU     Product     Price      Default     See details 2x3 A Hinge Kits SKU: 23AUPG Hinge Kits for 2x3 A style extensions. See details for size and color. Our price: $7.32  Buy Now  See details 2x3 B Hinge Kits SKU: 23BUCC Hinge Kits for 2x3 B style extensions. See details for size and color. Our price: $7.32  Buy Now  See details 3x4 A Hinge Kits SKU: 34AUCC Hinge Kits for 3x4 A style extensions. See details for size and color. Our price: $8.41  Buy Now  See details 3x4 B Hinge Kits SKU: 34BU2 Hinge Kits for 3x4 B style extensions. See details for size and color. Our price: $8.41  Buy Now