A good take by WYSHTECH Airsoft on the Solink Airsoft SR25 Helical Gearset which includes a test of product... "The Solink Airsoft SR25 Helical Gearset is built for platforms using 19-tooth sector gears like Cyma, A&K, and others—not standard AEGs. In this video, I install and test it inside a Cyma Platinum SR25 and compare it directly to the stock gearset. I’ll break down its build quality and include performance results to help you decide if it’s worth the upgrade."

Prime Mech Airsoft has introduced a limited-edition, long version of their Brushless x Helical KRISS Vector Upgrade, built upon the Krytac KRISS Vector platform. This upgrade features a Perun KRISS for enhanced performance, a Brushless SoLink 28k motor, and a Helical 16:1 SSG SoLink gear set, allowing the airsoft gun to achieve an output of 1.3J when using 0.30g BBs.

According to Prime Mechanics Airsoft this BCM Air MCMR 11.5 AEG Build With Helical Gears sounds like an HPA airsoft rifle. This build is equipped with an Aimpoint T2 Hollywarrior, Surefire M600, and Surefire SOCOM RC2 suppressor (Dytac). Other parts are a Gate Titan II Bluetooth, Begadi Mamba motor 28 tpa + Lonex Helical pinion, SHS 12:1 DSG, Lonex Helical (spiral) bevel gear, and MagicPad️. It has a power of 1.1J with 0.28g.

Another Airsoft Tech 101 lesson as part of the "Inside The Gearbox" series by The Airsoft Tech. Going inside the gearbox, he talks about Helical Gears and they do especially for high-torque AEG gearboxes. There are different sellers of Helical Gears so just be more discerning in choosing sets for your AEG.