The UBR 2.0 is an adjustable stock for the AR15/M4, designed to offer the same strength and stability as a fixed stock with a consistent and comfortable cheek weld in any position. An update of the revolutionary Utility/Battle Rifle (UBR) stock, the UBR 2.0 features a fixed cheek piece to provide a consistent cheek weld in any of its 8 positions, and is compatible with A5-length buffer systems. Designed to accommodate largebore AR calibers and withstand severe impacts, the UBR comes standard with front and rear QD sling attachment points, a recessed footmanâs loop, the ergonomic MOE SL angled-toe rubber butt-pad, and storage compartment.