Part number 28-E0300-7T-K is a Hydro Quip Low Flow Vertical 5.5kW 230V Titanium Heater Assembly.
This specific heater is designed for spas that use a 24-hour circulation pump and is an upgraded titanium replacement for several original equipment manufacturer (OEM) heaters.
The following hot tub manufacturers and brands have used this specific heater or compatible components in their spas:
Gatsby Spas: This is a primary brand for which the heater was designed as a direct replacement.
Blue Ridge Spas: Utilizes this 5.5kW low-flow vertical heater assembly in their models.
Leisure Bay: Known to be compatible with Leisure Bay spa heater systems.
Maax Spas / Coleman Spas: Several models under the MAAX/Coleman umbrella are compatible with this heater.
Jacuzzi Whirlpool: Compatible with certain Jacuzzi brand spa heater systems.
Sundance Spas: This part is cross-referenced as a replacement for certain Sundance models' heaters (e.g., replacement for 26-08174).
Dynasty Spas: Another manufacturer that uses this type of Hydro Quip low-flow heating system.
Other Brands: It is also compatible with spas from brands like Diamante, U.S. Tooling, Whitewater, and Echo