Mechanism: Twin Hammer / pinless /pinclutch optional Highest durable Japanese steel anvil (standard & 6" optional) Top exhaust or bottom exhaust Forward & Reverse : 3 positions for each side Heavy duty casting of housing Inside or outside trigger available Left / Right handle available Available for kit set : (sockets: 21, 22, 24, 27, 30, 36, 38, 41mm x 90L)