Finnex THD-500S 500 W Titanium Heater Element

Exact-model photograph is not verified. Text-only reference. The official Finnex THD family visual remains scoped to the full review but does not identify this selected wattage or an exact assembly/package, so it is not reused here.

Finnex lists the THD-500S as a 500 W heater element for 70–125 US gallons. Its 0.62-inch diameter and 12.5-inch length distinguish it from the same-wattage TH-500S, while the official Shop record says the element is sold without a controller.

Search results may include other models. Confirm the exact model, applicable region, condition and included parts before ordering.

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Documented model details

• Finnex lists THD-500S separately from its same-wattage TH-500S: THD-500S is 0.62 inch in diameter and 12.5 inches long, with a 70–125 US-gallon band; TH-500S is 0.75 inch by 14 inches and listed for 70–130 gallons.
• The THD-500S table row gives 500 W, 120 V, 4.5 A and the 70–125 US-gallon capacity band. The length is a published heater dimension, not an installation-clearance instruction.
• Finnex describes THD construction as titanium with an internal quartz sleeve; its family page says TH and THD models include a high-temperature protective guard and are for freshwater and marine use.
• The official Shop's separate 500 Watt option is SKU THD-500s (case retained), variant 51093135720747. The Shop describes the item as a heating element only and says controllers are sold separately.

Limits to weigh

• The manufacturer capacity range has a 70-gallon lower boundary. The current max-only finder cannot enforce that minimum, so this reference remains outside ordinary questionnaire matches rather than being treated as a recommendation.
• The 500 W Shop item is an element, not a documented complete temperature-control system. The reviewed sources do not establish a THD-500S-specific controller pairing or exact seller package contents.
• The family table gives 120 V and 4.5 A in separate columns without stating the current's reference condition; it gives no frequency. Confirm the actual unit and controller labels rather than expanding those figures into an unverified full electrical rating.
• The checked Finnex instructions index does not list a THD manual. Exact model-specific mounting, immersion mark, orientation, clearance, inline-filter use and dry-operation instructions remain unresolved, not inferred from another Finnex family.
• The official shared THD image does not identify the selected wattage or exact assembly/package, so no image is used on this text-only reference page.

Check before ordering

• Verify the model label says THD-500S and the selected item is the 500 W version; do not substitute the same-wattage TH-500S. The official Shop SKU capitalization is THD-500s.
• Check the complete 70–125 US-gallon maker band, including its 70-gallon lower limit; this reference is not a finder-validated fit decision.
• Treat the titanium element and external controller as separate components unless the exact offer documents otherwise. Confirm controller compatibility, load and included probe/parts for the actual package.
• Read the actual element/controller nameplates for full supply details and obtain the model-specific setup instructions before installation; the reviewed family table omits frequency and does not state the 4.5 A reference condition.
• If using an Amazon model search, inspect the result itself for THD-500S, 500 W, seller, condition, quantity and included controller/components; a result for TH-500S or another Finnex element is not the same product.