G&G ETU Upgrade kit Current batch comes with Tamiya connector unlike picture Our Upgrade Kit for G&G ETU enhances your trigger unit by adding several new options. Simply disconnect the stock electronic board and plug in our Upgrade Kit. The stock trigger unit is retained, so there is no need to open the gearbox. Possibility to set any combination of the following firing modes under "SEMI" and "AUTO" selector positions independently: - safe - semi-automatic - 2 to 5 round burst - full-automatic Programming of all of the settings, not only firing modes but also switching active brake, precocking and battery protection on and off is done solely by using easily memorable sequences of fire selector switching and trigger pulls. That allows changing the settings at any moment in a matter of seconds, even under enemy fire. Precocking. Fast trigger response can be a matter of victory or defeat, especially in CQB situations. With precocking enabled, piston will remain in rear position after each shot with spring already compressed, ensuring that next shot will be fired immediately after you pull the trigger. Precocking works in semi, burst and full-automatic modes. Battery protection mode, dedicated to Li-Po batteries. Should the battery voltage fall to a dangerously low level, user will be notified by short sound signals that are repeated every 30 seconds. This may also be freely switched on and off. Double shot mode allows for easy double shots in semi-automatic setting. After enabling this mode, if semi-automatic fire is set, shots will be fired not only when the trigger is pressed, but also when it's released. Upgrade kit works without problems with any battery from 7V do 17V. Even if the battery has only enough power to make the replica fire at a very low rate of fire, the circuit will work. It can also be used with most extreme setups, without any limitations as to the spring rating. The maximum rate of fire is 50 RPS. Electronic fuse designed to work with Li-Po batteries will save your replica and battery in case of a major malfunction. It will automatically disconnect the battery, if a short circuit or blocked motor is detected. G&G ETU has an active brake, which is retained in our upgrade kit. Active brake allows to stop the motor after each shot. In case of double shot problem in replicas with high rate of fire, active brake will be an effective solution. It can also prevent compression of the main spring for a longer time, if you will fire a shot with AB on before a storing your replica for a longer time. Active brake is can be switched on or off at any time in few seconds.