Castle Creations B-Link Adapter Kit

Weighing in at just 0.23 ounce, this Bluetooth adapter and free iOS app let you wirelessly adjust and program your Castle Creations speed control. Once downloaded, the app does not require a data connection and can be used anywhere, including remote areas, and it lets you quickly adjust settings without disconnecting or disassembling your aircraft. It costs $49.95. castlecreations.com