Ok I get that these come in 4 inch or 6 inch width.?is.how tall of a post do these cover.8ft post or 10ft post.will 1 kit work for 8ft tall 6x6 post.

Hello Nick, They come in both a 4" and 6" height for protecting the base of your post from string trimmer damage and providing a nicely designed trim piece. There LxW dimensions are made to fit the standard labeled 4x4 and 6x6 posts measuring 3.5" x 3.5" and 5.5" x 5.5".