This combo sensor includes both touch sensor and a piezo sensor. The switches are used to turn circuits on and off, and are connected in parallel; meaning that either switch will activate the connection.
The Moisture / Touch Sensor detects conductivity. Placing objects such as a finger or other items on the sensor pad will complete the circuit. When connected to a SnapCPU, the code can be used to measure the exact conductivity of an item.
The Piezo speaker plays sounds or can be used to detect impacts such as finger taps and drum beats.