Check the listing for details. Frog® @Ease® in-Line Mineral Cartridge + 3 in-Line SmartChlor Cartridges for Hot. Condition: New. Listed at 80.00 USD. The Frog® @Ease® in-Line Mineral Cartridge + 3 in-Line SmartChlor Cartridges is a set specifically designed for hot tubs, featuring an oval shape and a 3-inch diameter. This product, from the brand Frog, includes a mineral cartridge and three smartchlor cartridges for maintaining clean, sanitized water in your hot tub. The in-line design allows for easy installation and efficient purification, making it a convenient and effective solution for keeping your hot tub water crystal clear and safe for use.The Frog® @Ease® in-Line Mineral Cartridge + 3 in-Line SmartChlor Cartridges is a set specifically designed for hot tubs, featuring an oval shape and a 3-inch diameter. This product, from the brand Frog, includes a mineral cartridge and three smartchlor cartridges for maintaining clean, sanitized water in your hot tub. The in-line design allows for easy installation and efficient purification, making it a convenient and effective solution for keeping your hot tub water crystal clear and safe for use.