The description says the manufacturer is Sundance but the heater I received is NOT the original. I received a heater of a different brand that doesnt fit with my Sundance model. The problem is that it doesnt come with the hi-limit sensor that is supposed to come with this package !!! the description says the heater will retrofit old sundance spas but this is NOT the case because it comes without the sensor, so the old sensor doesn't fit !!

Here's more information about the 6500-310 heater and the hi-limit sensor:
This smart low-flo heater assembly is a compatible replacement for the 6500-310 heater in Sundance Spas 850 and 880 series models from 2000 to current. The Smart heater comes with the high limit disc and the red and black wires to connect it to the circuit board. Some of the early models of the 6500-310 heater found in Sundance spas before about 2002 have a high limit temperature probe inserted into the hole beside the hi-limit disc that is connected to the circuit board. This heater does not come with the high limit probe that connects to the circuit board on the pre-2002 models. If your Sundance spa model has the additional hi-limit probe, it can be removed from the old heater and installed in this heater. On hot tubs that have the additional hi-limit probe it is required and cannot not be deleted.

Bought this a year ago and just quit on us..... furious!!

Drop in replacement and works fine so far but does not come with temp sensor and the recommended one that I purchased is not the correct one. I removed and installed the old sensor and everything is working fine.

Works and fits

Great product.