This product is a 360 degree rotating stock that offers adjustable length and an adjustable cheek rest platform. All adjustments offer markings so various users can remember their preferred settings. The primary purpose of the stock is to allow for users to wear a full M50 gas mask without hindering their aim. Since the stock can be rotated, room can be made for the mask while still resting your face for a perfect line of sight through scope to target. These stocks are designed for all shoulder fired weapons