74mm S&P Spa Bath Jets. Has adjustable Faceplate. Originally came in white, cream, or chrome. Now are all chrome. They have approx 74mm Diameter face. There was also a version with "Monarch" in the face.
To remove these jet internals, insert a small flat screwdriver inside the eyeball into plastic D ring. Then pull screwdriver blade towards centre to unlock the jet. Simply pull out.
Important: Newer jets may have a longer tail than your old ones. If this is the case, simply trim off some of the tail piece to fit new jet internals.
S & P Spa Bath Jets, Monarch Spa Bath Jets