Optional Ø61mm rings can be used to increase the PWC’s power. It is recommended for Sea-Doo spark Flyboard® kit. Using the Ø61mm rings can lead to vibrations on other regular PWCs non-equipped with a dual impeller. Standard (not for SeaDoo Spark) Flyboard® and Jetpack by ZR® bundles are supplied with Ø61mm Nozzle Rings. Product includes: Nozzle Rings (2) Nozzle Screws (4)