Always match the heater number to ensure the correct specification, the 3kw can be used with GS500, 500Z, 501, 501Z (3.0KW only), 501SZ, 510, 510S, 510Z, 510SZ, 511SZ, 523DZ, GL2000 mach 3, GL2001 mach 3 systems, it is used in spa including Spaform, Hydrospa, Canadian, Aegean, Catalina, Hydropool,, Marquis Spa,, Leisurite, Leisure Bay, Signature Spas, Hot Tubs Direct.
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