Cedar planks are great for the outdoors, they do not rot and are a flea deterrent. The standard planks are milled 1" thick by 8" wide. Milled wood is slightly smaller than the measurements given. Wood is priced and provided with all the appropriate hardware for shelving. Brackets, hardware, and screws included. The number of brackets included with each shelf is dependent on the length of the shelf: 8" wide shelves from 12" to 60" in length require 2 brackets (one on each end) 8" wide shelves from 62" to 92" in length require 3 brackets (one on each end and one in the middle for added stability) 12" wide shelves from 12" to 46" in length require 2 brackets (one on each end) 12" wide shelves from 48" to 70" in length require 3 brackets (one on each end and one in the middle for added stability 12" wide shelves from 72" to 92" in length require 4 brackets (one on each end and two in the middle for stability 8" wood is nominal 1x8 = Actual size is 7.25" x 0.875". 12" wood is nominal 1x12 = Actual size is 11.25" x 0.875". NOTE: 12" wide shelving should be ordered as long as the catio side whenever possible (i.e. a 92"L shelf for a 92"L catio side) to be adequately supported.