Durable and Impact Resistant Glass Fiber Reinforced Matte Black Polymer Construction. Four-way Anti-tilt High Visibility Blue Follower and High Longevity Stainless Steel Spring for Reliable Feeding. Features Positive Grip Texturing, Left and Right Side Windowed Main Body with Remaining Round Count Indicators, Over-insertion Stop, and Removable Flared Floor Plate. *Not Compatible with AR-10B, SCAR 17S, LAR8, HK417, or Rifles that Use M14, FAL, or HK G3/91 Patterned Magazines