Makita HM1214C Demolition HammerHeavy duty demolition hammer with AVT The AVT (Active Dynamic Vibration Absorber) is a mechanism that absorbs vibration through a balancer held by springs. When the striker and the piston move back & forth, positive and negitive air pressure is created in the barrel and crank area. This pressure causes the balancer and springs to move in the opposite direction of the force to constantly counteract the vibration. Features: AVT ensures extra low