Widely Compatible with Frog ease,Artesian Elite,Island,Marquis Crown ,Marquis Elite,Vector＆Celebrity,Caldera Vacanz and Hot Spring etc. Long lifespan:Included 3 Replacement Cartridges each lasts up to 3-4 weeks depending upon hot tub size and usage.Ideal UP for 600 Gallon hot tub. Plug-and-Play Simplicity: Easy to set up. Effortless Upkeep: Just replace the cartridge as needed. After-Sales Service: When you have any questions about the product, please contact us, our professional team is dedicated to providing 7-24H support to you Package Content： 3*Replacement Cartridges.