This filter cartridge is for Spa2Go or Spa-N-A-Box Portable Spa and is an easy way to extend the life of your hot tub while ensuring a clean and enjoyable environment. Long-lasting and efficient, these spa replacement filters are convenient and easy-to-use.\r\nDiameter: 4 7/16"\r\nLength: 7" (8" including the foam)\r\nTop: Open Hole: 2"\r\nBottom: Open Hole: 2"\r\nUsed in these spas: Spa2Go (blue or green). 6 ft. Spa-n-a-Box #CLP250-C, EZspa, GR8spa, STG1 STG2 STG3