This air jet has a single opening that makes big bubbles, unlike the "pepperpot" style jets, which have a lot of small holes.  It is often used as an outlet for the ozone injection system.

It consists of a grey jet and a white socket, which mounts under the spa shell.  The two parts are delivered together, along with a flat gasket (to be mounted inside the spa) and an o-ring (to go under the shell).

Connect this jet either to an ozone injector or to a manifold using 3/8" flexible pipe.

Dimensions
Pipe connection: 3/8" male (10 mm external diameter)
Part that goes through the shell: 18 mm external diameter (requires a 18-19 mm hole)
Jet diameter: 37 mm
Jet opening (where the bubble come out): 10 mm
Socket length (space required under the shell): 50 mm

Waterway product codes
Entire kit with jet, socket and o-rings: 672-2200
Jet body (socket) : 672-2200
Flat gasket : 711-1350