Easy-Lok lid access design provides simple entry to service the cartridge element * Built-in check valve prevents accidental loss of pool water when cartridge is being removed for cleaning * Unique safety-catch prevents over tightening of the cover and unwanted entry into the filter * Cartridge element is uniquely designed of high quality reinforced polyester and a molded center core for easy cleaning, high flows and long life. * Union connection allows pump or filter to be removed quickly and easily for servicing systems