2560-040 Flow Switch Replacement Part Kit for Sundance Spas and Jacuzzi Hot Tub Features: 1）Spa Flow Switch Replacement Kit-- This complete flow switch replacement kit is made of a high-impact surgical plastic housing, clear plastic for easy viewing of any debris in the switch. A defective flow Sensor will cause a "Flashing Flo" or "Solid Flo " on the Control Panel Icon, It is time to replace your old flow switch if you get a "Solid Flo" error. Save you from a clogged or defective circulation pump, or dirty spa filter. .