Micro Clean Ultra Inner Core Filter. This filter is not a reproduction like many on-line stores carry. This filter is a certified O.E.M filter straight from the Sundance factory and is engineered with a proprietary filter chamber that is designed to pull the correct amount of water through your pump in-order to elimate pump failure un-like many other reproductions or non-Sundance Filters.
**This filter can only be used with the Micro Clean Ultra Outer Core Filter
**This filter fits all 2005+ 850/880 Series Spas