Designated Marksman Rifle buttstock. Designed for 5.56 caliber rifles with carbine extension tubes. The DMR stock has comb height and length of pull adjustments for fine tuning of the shooter experience. Shooters looking for a simple tool-less upgrade to their long range rifles love this stock. There are many rifle stocks on the market, but none like this. No change of buffer tube required, will replace any collapsible 6 position mil-spec stock.