This spring wound timer allows users to set fans, HVAC, whirlpools, motors, pumps and other appliances to automatically turn off, helping to save energy and money. The easy-to-use, twist dial timer features easy wiring with no neutral required, ideal for retrofitting existing wall switches. This timer is designed to replace any standard single or multi-gang wall switch. The 2-in-1 switch configuration wiring can be used for SPDT and SPST.