The 8 tooth SiegeTek Cyclone Dual Sector Gear features two sets of 8 pick up teeth on the gear, this allows for two shots for every rotation of the sector gear. SiegeTek gears are CNC milled from high strength nickel chromoly steel. These gears will work with both 18:1 and 16:1 gear sets and will essentially double your rate of fire. Dual sector gear build requires a very strong gearbox so other upgrades like our SHS 15-Tooth steel piston. Do NOT use with any spring under M150 unless utilizing a spring spacer system.