This sensor is a Metal Touch Interface module and number 13 comes with LED build a simple circuit to produce a touch cue lights and comes with digital interfaces of the LED, the metal touch sensor connected digital three interfaces, when a metal touch sensor senses a key signal, LED lights,

This sensor is a Metal Touch Interface module and number 13 comes with LED build a simple circuit to produce a touch cue lights and comes with digital interfaces of the LED, the metal touch sensor connected digital three interfaces, when a metal touch sensor senses a key signal, LED lights, otherwise off.Specification:Color: Red BlueMain Chip: LM393Working Voltage: DC 5V