Exciting new electrical retracts that weigh only 6.5 ounces for the total setup. Each strut has almost an inch of downward spring loaded travel for maximum shock absorption. Installation is as simple as mounting into your model and connecting the 3 retract units servo wire plugs into the master retract controller then plugging controller into your receivers gear channel. No air tanks, air lines, or complicated setups. Does require one servo for the nose steering. Struts are removable from retract unit allowing you to customize for your particular application.