Feature APPLICATION: The 72602 spa ozone system replacement is compatible with Hot Spring spa models 1994-Current, for Tiger River hot tub spa models 1995-2010, for Limelight hot tub spa models 2008-Current, and for Hot Spot spa models 2010-Current, for Caldera hot tub spa models 2010-Current. FUNCTION: The 72602 ozone system produces ozone differently than today's UV-type ozone generators. The corona discharge method produces higher concentrations (PPM) of ozone, and the concentration levels do not decrease over time as UV ozonator do. Keep your water clean and clear, while reducing the need for chlorine. .