How FAST does your rocket fly?! Track the speed of the Speed Freak rocket using the Advanced Velocity Tracking Technology capsule. The capsule contains a digital speedometer that records the speed of your rocket, flight after flight. It's simple to use and can track velocity on each launch. Compare how one engine stacks up in speed to another engine, which engine makes the rocket go faster? The electronic speed-tracking capsule is boosted skyward on the Speed Freak rocket and is jettisoned during the ejection phase. The capsule then returns via a streamer and upon impact, it calculates the maximum speed of the rocket. The reading is displayed on the LCD screen in MPH and KPH, alternating between the two every 2 seconds. The Speed Freak rocket returns on a 12-inch parachute. The Speed Freak capsule can also be used on Estes rockets with a BT-56 size body tube (1.35 inch diameter). The Speed Freak comes complete with Speed Freak RTF rocket, speed-tacking capsule, button-cell battery, launch system and supplies for your first two flights. Minor assembly is required.