This section contains jets from Pentair American Plastics, now Hydroair International and Balboa Water Group.
They are quite large jets with a distinctive rear part.
They fit and release into the hot tub by means of a plastic spring located just inside the front face.
Once the spring is held open these jets push in and pull out. If the elasticity of the plastic spring wears out, the jet will pop out from water pressure - this is a sure sign that the jet needs replacing.