Stocks are `standard`.... which is why guys order custom-made, i.e. so system is made to customers` specifications and [importantly] follows the contours of the individual skull-shape for a good fit....... density on stocks is medium, freestyle, and [ I think] bodywave. They come in two sizes..you measure your thin/bald area front-to-back and side-to-side.....the nearest size in a stock will be sent ....this means you may possibly have to cut/trim the base. Paul.