Check the listing for details. Heshan Lide Fog Machine Timer Duration Interval Switch UL 120V FWC-4(5724006). Condition: Used. Listed at 19.87 USD. The Heshan Lide Fog Machine Timer Duration Interval Switch is a wired control device designed for fog machines. With a manual control feature, this switch allows users to set the duration and interval for the fog machine's output. Operating at 120V, this UL-certified product by Heshan Lide Electronic provides a reliable and efficient solution for controlling fog machine effects in various settings such as stage lighting and special events.