The Midwest Industries Stock Tube Adaptor Picatinny allows the user to mount stocks that use buffer tubes on weapons that have picatinny attachments. This is not intended for weapons like the AR-15 that use a normal buffer tube. The Stock Tube Adaptor provides a 6 position Mil-Spec diameter tube with easily accessible waterproof storage in the tube. Constructed from hard coat anodized 6061 aluminum. Overall Length 6.750 inches and weight of 7.5oz. Made in the USA.