Sundance® Spa and Jacuzzi® Hot Tubs changed from the 6540-966 to this diverter in Early 2018+.
Is your diverter leaking? This is the repair! This is compatible with any spa that originally had the 6540-966 diverter.
Newer Water Diverter Valve, preferred over the discontinued 6600-966 Valve. This Valve is designed for self-cleaning and should fix any leaking diverter issue.
The redesign has holes for self-flushing of debris through valve rather than depositing sand and grit in the valve, making it impossible to turn.
The valves are interchangeable with either the 6000-104 or this one.