MPA’s Ultra Bag Rider combines the benefits of the Enhanced Bag Rider design along with a minimal Butt Hook feature. This design provides a solid rear support when used with a rear bag when the shooter wants to pull the rifle into the shooters shoulder, improving accuracy performance due to the consistent shoulder pressure applied using this accessory. This Ultra Bag Rider works with all BA, BA Comp, ESR, BA Hybrid & BA lite chassis that have a 3 hole pattern on the bottom of the buttstock. MasterPiece Arms Ultra Bag Rider II w/(2) Socket Head Cap Screws & Turned Step Shaft BAGRIDER-ULTRAII in Black