Budding airsoft techs can watch this video by Fulcrum showing how to install a MOSFET on an AEG... "In this #airsoftguide I will be installing a basic airsoft MOSFET into the wiring loom of my CYMA M14, the reason being is the contacts aren't going to last much longer without one. Switching DC mechanically has the downside of arcing (AC can still arc but nowhere nearly as bad as the voltage drops from the AC waveform), especially when the load has inductive properties. In an airsoft AEG the motor can draw a ridiculous amount of current when the gun is fired, add the induction of the motor and the trigger contacts can suffer significant arcing as they disconnect.

Arcing on the trigger contacts of an airsoft AEG can wear away at the contacts, causing carbon build-up which can increase the resistance of the contacts and over time the pitting will eat through the contacts until they eventually fail. Fitting an airsoft MOSFET is the best way to eliminate this wear and tear as well as making your airsoft gun generally more responsive.

A basic Airsoft MOSFET acts like an electronic switch, the trigger contacts no longer have to handle the motor current, instead the contacts only have to switch a tiny trigger current which won't arc across the contacts. When this trigger current flows, the MOSFET chip conducts and allows the high current to pass through to the motor, when the trigger contacts part the circuit opens and since it is solid state, no arcing occurs.

The MOSFET in this video is a basic Xcortech Nano, nice and simple with no silly features which I don't need. Got a very similar Xcortech MOSFET in the Uberwomble switching a very similar GFC motor. Definitely a good MOSFET."