UBR means Utility Battle Rifle. It is a fully-featured, adjustable butt stock for the AR15/M16. Unlike typical collapsing stocks, this modular design offers the stability of a fixed stock with consistent cheek weld in any position. Seven-position length-of-pull (LOP) adjustment is quickly executed with gross motor movement while the integral preset system allows direct access to a preferred position. A robust lock mechanism and multi-shell construction increase overall durability. Suitable for M4 or M16 airsoft guns. China made replica for airsoft toys only.