VFC Quick Response System QRS Stock (Black / Tan)The VFC QRS Stock well adjust by pressing the latch in the middle which looks like a large trigger and it'll slide along any stock tube out there. You can also open the butt pad which has ample room for any type of battery and makes things easier when it comes to battery changes. The stock suits all Mil Spec buffer tubes. There is a small rail system on the bottom for a vertical bipod making it easier for you to balance your rifle if you are using it