The 1x6 strop is mounted on Aluminum blanks. I'm extremely pleased with how these came out. I've selected extra thin Kangaroo leather specifically because it is so thin that the amount of 'give' is minimized. Smooth? You bet! Some of the smoothest leather I have ever felt. I'm considering it an ultimate strop, especially well suited for ultrafine compounds below one micron going all the way down to my finest compounds (0.025 microns - ten times finer than quarter micron). In the extreme, it can also be used without compound and has the 'draw' associated with leather. Pictures can't truly capture the smoothness, which must be touched to truly believe just how fine it is.