Siegetek Concepts is a US company that specializes in high precision premium mechanical gears for electric airsoft guns. In addition to superior designs and quality material selection, we heavily use CNC machining and minimize sintering for the production process. In fact, Siegetek Concepts is the only company in the industry that currently produces fully CNC machined nickel chromium molybdenum steel sector gears for unprecedented durability. Our standard nickel chromium molybdenum steel gear sets offer the following benefits: Precisely calculated and accurately produced gear teeth in volute profiles provide maximum efficiency and durability. CNC machined and case hardened sector gear offers increased durability over traditional powder metallurgy sector gears. Enlarged sector gear release tooth provides enhanced strength to cope with the accumulated spring load at the end of piston cycles. Shape-optimized power cut-off cam decreases cut-off lever reset time, which reduces the chance of trigger switch jam. Enlarged tappet cam increases the tappet plate and nozzle retracted time for better ammo feed (Revolution Plus and Revolution sector gears only) Increased gear thickness provides higher bearing surface and improves structural durability. For TM V2/3 And Compatible Mechboxes: For TM V6/7 And Compatible Mechboxes: Revolution Plus (10.44 ratio) Recommended max spring rate: 1.10 Joules (M105) Revolution (14.09 ratio) Recommended max spring rate: 1.21 Joules (M110) Revolution (13.76 ratio) Recommended max spring rate: 1.21 Joules (M110) Balanced (20.8 ratio) Recommended max spring rate: 1.69 Joules (M130) Balanced (20.81 ratio) Recommended max spring rate: 1.69 Joules (M130) Torque (27.5 ratio) Recommended max spring rate: 2.56 Joules (M160) Torque (27.08 ratio) Recommended max spring rate: 2.56 Joules (M160) Torque Plus (40.91 ratio) Recommended max spring rate: 4.41 Joules (M210) Torque Plus (42.43 ratio) Recommended max spring rate: 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 TM stock motor performance. The gear sets may be paired with higher spring rates when higher performance motors are used.Specifications: Manufacturer Part#: GS-T-EMaterial: CNC Nickel Chromium Molybdenum Steel Ratio: 26.67 / Flat / Torque Gearbox compatibility: Elongated Gearbox ie. SR25/AR10 Style AEGClick here for Gear Installation NotesNote: Professional Installation of Siegetek Gears Highly Recommended.