Compact size (size of two M4 magazines) fits into most M4 AEG receivers Internal electric winding mechanism automatically winds with the sound from your AEG Integrated low profile dual magazine clamp Dummy 5.56 dummy bullets Manufacturer: JG / Matrix Specifications: Dimensions: 185mm L x 60mm H Compatibility: Works with Tokyo Marui, Matrix, G&P and other compatible M4 / M16 AEG rifles Capacity: 800 rounds Battery: 4x AAA (batteries and charger not included) Activation Mode: Sound: Auto-Wind Materials: High strength polymer