For those who strive for improved trigger response and rate of fire performance, we offer the Cyclone Dual-Sector Gear System. The Cyclone Dual-Sector Gear, in addition to retaining all of the benefits of our standard gear sets, provides the following advanced features: Cyclone Dual-Sector Gear Evolutionary Dual-Sector design allows unprecedented ROF potential with two shots per sector gear cycle! Half-cycle cut-off system retains semi-automatic fire functionality. Dual short stroke design provides improved system efficiency for short barreled systems. Gear profile design ensures compatibility with common spur-cut standard and high speed ratio gear sets. The Cyclone Dual-Sector Gear System is designed for AEGs with 363mm or shorter barrels. Due to super short stroked nature of the design, the system requires higher rate springs for operation. Optional piston spacers (PS-8P) or spring guide spacer (SGS) specifically designed for thrust bearing equipped spring guides may be purchased to pre-compress the spring for higher energy output from lower rate springs. For TM V2/3 and compatible mechboxes: For TM V6/7 and compatible mechboxes: Revolution Plus (10.44 ratio) Recommended max spring rate (w/ PS-8P or SGS): 1.21 Joules (M110) Recommended max spring rate (w/o PS-8P or SGS): 2.25 Joules (M150) Revolution (14.09 ratio) Recommended max spring rate (w/ PS-8P or SGS): 1.44 Joules (M120) Recommended max spring rate (w/o PS-8P or SGS): 2.89 Joules (M170) Revolution (13.76 ratio) Recommended max spring rate (w/ PS-8P or SGS): 1.44 Joules (M120) Recommended max spring rate (w/o PS-8P or SGS): 2.89 Joules (M170) Balanced (20.8 ratio) Recommended max spring rate (w/ PS-8P or SGS): 2.25 Joules (M150) Recommended max spring rate (w/o PS-8P or SGS): 4.41 Joules (M210) Balanced (20.81 ratio) Recommended max spring rate (w/ PS-8P or SGS): 2.25 Joules (M150) Recommended max spring rate (w/o PS-8P or SGS): 4.41 Joules (M210) * Lower gear ratio indicates lower torque and higher peak RPM. Higher gear ratio indicates higher torque and lower peak RPM. Spring rate recommendations are based on typical neodymium magnet equipped motor performance. The gear sets may be paired with higher spring rates when higher performance motors are used.Specifications: Manufacturer Part#: GS-B2-CMaterial: CNC Nickel Chromium Molybdenum Steel Ratio: 20.16 / DSG (Double Sector Gear) / Cyclone Balanced Gearbox compatibility: Version 6 and 7 Click here for Gear Installation Notes Note: Professional Installation of Siegetek Gears Highly Recommended.