System accessory GCT 30-42. When you work with a vacuum cleaner, you usually have to operate both your tool and the vacuum. That's why we developed Auto-Start, to wirelessly synchronize battery-operated devices and vacuums, allowing them to start and stop automatically at the same time. The GCT 30-42 Professional Auto-Start module can be easily attached to many battery-operated devices using the three included rubber bands. Quickly pair the GCT 30-42 Professional with an external Auto-Start plug or a connected vacuum with just the press of a button. And you're ready to go! The Auto-Start module detects vibrations from the running tool and automatically turns the vacuum on and off for you. This way, you can fully concentrate on your work. Auto-Start manages your vacuum while you focus on drilling, chiseling, cutting, or sanding. You can use Auto-Start anywhere you need a battery-operated device in combination with a vacuum. 3 x flexible rubber bands. 1 x 3 V CR2032 lithium button cell battery.