The A.R.M.S.(R) #40(TM) Stand Alone Flip-Up Sight utilizes the same well proven concept as the rear sight on the Swan(R) Sleeve System. The unique design of the spring loaded rear sight ensures constant in battery action and repeat zero. The sight is held in the locked down position by a quick release lever that prevents the sight from being accidentally engaged" but is as fast as a trigger to release even with arctic mittens. Has horizon line notch" 500-600 meter sight. Windage adjustments .75 MOA."