Check the listing for details. (2pack) Chlorine Filter Cartridge for FROG @Ease Floating System, 2-Pack. Color: Gray, Condition: New. Listed at 51.94 USD. 2) SmartChlor Replacement Cartridges Condition: Brand New Keep your hot tub water crystal clear with the SmartChlor system! These gray cartridges are designed specifically for hot tubs with a built-in In-Line System (commonly found in Marquis, Caldera, Artesian, and Hot Spring Spas). Key Benefits: • CYA-Free: Uses a unique form of chlorine that doesn’t build up cyanuric acid, meaning you won't have to drain and refill your spa as often. • Self-Regulating: Automatically maintains a low, consistent chlorine level (up to 75% less chlorine than traditional methods). • Longevity: Each cartridge lasts approximately 3-4 weeks depending on spa usage. • Gentle on Skin: Significantly reduces odors and helps water feel softer. Chlorine Filter Cartridge 2-Pack