This Lay-Z-Spa Pump is a replacement for the heater pump supplied with Lay-Z-Spa HydroJet Pro 2021 models. It is essential for heating the water, filtering the water and operating the massage system. If your existing pump is damaged, this replacement is a vital piece of equipment. Without a working pump, you'll be unable to use your Lay-Z-Spa. The pump also has a timer function to heat up the water at a designated time. It's a great way to ensure the water is at the perfect temperature before you climb in. This pump is equipped with the new Freeze Shield technology, which allows you to set the pump to run at a low temperature, in a power-saving mode for long periods of time using minimal energy, whilst ensuring that the water does not freeze (the pump must be powered at all times).