KDD4 / Keystone Quad Mount Post Set Products » Gaines » KDD4 / Keystone Quad Mount Post Set KDD4 / Keystone Quad Mount Post Set $599.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30 40 50 75 100 Keystone Series Quad Mount Post Set – Heavy Aluminum Construction. Textured Powder Coat Finish. KDD4 includes 2 posts, 2 Finials, 2 Cross Beams, 4 Curved Braces, 1 Two-Mount Beam, and 2 Post Cuffs.