The high temperatures and chlorine in your hot tub can fatigue the plastic clip which holds the spa jet in place. If you are having trouble with your Waterways jets popping out, this may be the solution. Remove the diffuser from the back of the jet and replace it.

This diffuser fits the Waterway Power Sstorm series of jets used by many manufacturers. It is not compatible with backlit jets.

This diffuser is 6.5 cm in diameter and 10 cm long.

Waterway Power Storm jets measure approximately 5" (127mm) across and come in several different designs.

The Waterway part number for this diffuser is 218-6610.
Power Storm jets generally have a part number in the format 212-6XXX or 212-7XXX.