2-Pack Clarathon Premium Filters Handle top - 50 SqFt media 6" W - 8-1/4" L 1-1/2" (nominal) Coarse Threaded fitting Best Quality 12-month filter life Clarathon Premium Ultra Filters are the most effective and durable pool and hot tub spa filter cartridges available. In fact, you cannot buy a better quality filter at any price. Tips: Keep spares on hand. When you change your spa water, always rotate the soiled filter out with a clean, dry spare. The result is longer filter life and no waiting.