Enhanced Cylinder Tuning Set for G36C end of year sale M31 features several design solutions: Kleur:Everglade M31 features several design solutions: Low profile ambidextrous construction for ease of use of firearms A waterproof battery compartments Three sound amplification levels Two reinforced microphones for enhanced situational awareness Battery saving mode Adjustable headband Integrated 3 Weight: 930 g Shipping weight: 930 g Weight: 33 g Shipping weight: 80 g