Waterway Directional Power Storm Snap-In Jet Insert (includes diffuser). 

Waterway Plastics discontinued all Snap-in Cluster Storm Series Jets, except this model (to install, push in and rotate a 1/4 turn clockwise). To remove jet, rotate counter-clockwise (about 1/4 turn until it stops) then apply additional turning force to unlock. If you have Snap-in style jet housings, you must use Snap-in style inserts (the newer threaded style inserts will not fit).