hey would be either 12 or 15". I usually try to make them a width that holds the chrome pull out pantry hardware. 12 and 15" wide units hold the same basket width, as do 18 or 21" units - so if you want to use space someplace else it is wise to use the smaller numbers. if you are not looking to use commercially available pull outs, but have custom ones made, then it's totally up to you and your space.

I love the silver can lights kits....where can you get these??