Black Ops M4 Diamondback Airsoft AEG Rifle - Electric Fully Automatic Airsoft Gun - Upgradeable Gearbox and Internals - Shoot .20 .25 BB Ammo SOLID BUILD QUALITY WITH FULL METAL - Upper and lower receivers, buffer tube, outer barrel, RIS rails, gas block, and flip up sights are all metal, and built to last. FULLY UPGRADED GEN 3 GEARBOX WITH 8mm metal bearing bushings, metal spring guide, upgraded metal piston head, cylinder, and cylinder head, and pre-shimmed all steel gears. LONG RANGE ACCURACY AND CONSISTENCY - Metal wishbone hop-up that eliminates creep while improving consistency and range, new high-torque long-axle motor, ready for LiPo batteries and .25g or heavier ammo. HIGH POWERED RANGE WITH OVER 370FPS with .20g BBs, tighter 6.06mm ID metal barrel, and more than 600 rounds per minute on full auto. INCLUDED 1 YEAR WARRANTY AND ACCESSORIES - M4 Diamond Back AEG, Hi-Cap 300rnd Magazine, Manual, 100 6mm BBs, Cleaning/Un-Jamming Rod