The Max-Thrust electronic retracts are sealed electronic units that do the difficult part for you, all moving parts are internal to protect them from knocks and bumps, and installation is as simple as plugging into an auxiliary socket on your receiver. Supplied as either a set of 3 units or individually and capable of supporting 2.5kg of model, these retracts are perfect for any scale build, especially when paired up with the Max-Thrust Scale Legs.