The Sig Sauer MCX Spear-LT Lower features a fully ambidextrous controls and rear QD point for slings, 1913 3-slot Pic rail for attaching stock adapters. This lower includes the factory packaging and one 30rd 5.56x45 magpul magazine. These lowers are compatible with any Spear-LT Upper making it easy to switch between calibers like 7.62x39mm, 5.56x45mm NATO, 300 Blackout.