Guntec USA AR-15 Essentials Kit is an upper parts kit offering a Gen 3 Gate and Mil-Spec Buffer Tube complete assembly, 5.56 charging handle, extended takedown pin set, anti-rotation pins, extended magazine catch release, extended bolt catch release, and an enhanced trigger guard. Caliber is 5.56x45mm NATO. Weight approximately 20 oz. Compatible with AR-15 platforms. Finish options include blue, clear, red, purple, grey, cerakote FDE, gold, green, and more. This kit upgrades or assembles an AR-15 upper receiver with quality parts and does not constitute a complete firearm.