FROG @Ease in-Line Sanitizing System for Hot Tubs, for use in Marquis Spas, Caldera Spas, Artesian Spas and Hot Springs Spas up to 600 gallons, Hot Tub Sanitizer, Cyanuric Acid FreeBrand: FROG Color: Multi Features: For use only in certain hot tub models up to 600 gallons: Artesian Elite, Artesian Island (optional on Artesian Island Elite and South Seas); Marquis Crown (optional on Marquis Elite, Vector and Celebrity); Caldera Vacanza; and Hot Spring Hot Spot The FROG @ease In Line Sanitizing System includes 1 Mineral Cartridge that lasts 4 months, 1 SmartChlor Cartridge, that lasts up to 4 weeks depending on hot tub size and