Perun, a small Poland-based company, makes excellent and extremely compact mosfets for Airsoft guns. They were very kind in sending me their ETU++ mosfet to review. It is intended to be a drop-in mosfet for G&G AEGs with an existing ETU. This plug and play unit gives you loads more functionality than the stock G&G mosfet and is much more compact. Enjoy the review!
Check out the mosfet here: