The Aero Precision M4E1 Complete Lower Receiver with ALG QMS Trigger is the perfect base for your AR build. This complete lower features an M4E1 Lower along with the A2 Grip.Includes: M4E1 Lower Receiver A2 Grip Lower Parts Kit Carbine Receiver Extension AR15 Carbine Buffer and Spring ALG QMS Trigger NOTE: This complete lower does not include a stock. Save on your initial purchase and choose any stock you prefer!