Rock River Arms AR0074K
Rock River Arms AR0074K features a trap door on the rear of the stock, you can add an optional weight to the stock body. It also has a sling loop so you are ready to go if you run a sling on your AR-15. The stock body is gray, but I have read where some people oil them to make it a darker color. I have not done that, so I can not tell you if or how well it works.
AR0074K A2 Stock Kit
This A2 stock installs like any other A2 stock and is great for hunters, precision shooters and those who live in areas where they restrict adjustable stocks.