Darlly 60401 FC 0359 6CH 940 PWW50 Spa Pool Filter Cartridge lascofittings The Hydro Quip Versi Heat electronic retrofit The Hydro Quip Versi Heat electronic retrofit kit is designed for compatible heating applications where a 15 inch by 2 inch heater with a 9 pin connection is required The 91691201 is an excellent choice for service professionals and experienced repair buyers who want to restore proper flow in a compatible 1 The reference based fit gives this cartridge practical value because accurate filter replacement depends on matching the cartridge to known application numbers and this Darlly cartridge is designed for compatible applications referencing FC 0359