KD3 / Keystone Triple Mount Post Set Products » Gaines » KD3 / Keystone Triple Mount Post Set KD3 / Keystone Triple Mount Post Set $349.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 20 25 30 40 50 75 100 Keystone Series Triple Mount Post Set – Heavy Aluminum Construction. Textured Powder Coat Finish. KD3 includes 2 posts, 2 Finials, 2 End Caps, & 1 Three-Mount Beam.