This digital handheld salt meter is designed to use with Hayward Goldline Aqua Trol salt chlorine generator models AQ-TROL-RJ, AQ-TROL-RJ-TL, AQ-TROL-HP, AQ-TROL-HP-TL and also compatible with Hayward Goldline Pro Logic automation models PL-PS-8, PL-PS-8-V.