Estes Flying Model Rocket Kit Pro Series Star Orbiter 9716 We continue to develop and grow the Pro Series II line! This time around we're offering up a BT60 (1.64 in/42 mm) diameter body tube for your building enjoyment. Standing over 45 inches tall, the Star Orbiter comes with the quick release motor retention system just as the other Pro Series kits do. (Motor Retainer Set - is also sold separately). Construction of this kit is not difficult and the altitudes you will reach are very impressive! Building and finish work can easily be accomplished over a few days. Pro Series II Length: 45.2 in. (114.8 cm) Diameter: 1.64 in. (42 mm) Estimated Weight: 5.9 oz. (167.2 g) Laser cut Wood Fins, Screw on Motor Retainer, 15 in. (38 cm) Parachute Recovery Recommended Engines: E16-6 (first fight) F15-8