ECOSPA Thermostatic 2 Way Shower Valve with Large 300mm Thin Shower Head Handset Shower Valve Benefits Thermostatic Mixer Valve allows for a user set temperature that will remain constant regardless of any change in water pressure. e.g. due to a toilet being flushed, which would normally cause a fluctuation in temperature Anti-Scalding Device which is especially useful for children or the elderly who generally have thinner skin, allowing them to shower safely without being scalded Non-Return Valve this feature protects the valve from being damaged as well as providing protection against back-flow; water can only ever flow in one direction, out and onto you 2-Way Mixer this particular shower valve allows users to switch between a shower overhead or handset Features.