StratoFins Screw-on Water Rocket Fins + Parachute Kit Compatible with 95% of all available launchers either homemade or commercial. Works with various styles: cable ties, rubber stopper, expanding tube, nozzle, or O-ring. No tools or glue required for assembly, simply screw-on to a 2 liter soda bottle or smaller. 24" red Rip-stop nylon parachute with 6 sides and 6 braided nylon shroud lines. Shroud lines loop over fins attached to a 2 liter bottle and gathered at the top with a cable tie.