Check the listing for details. Magnetic Holder Bed On/Off Switch Holding Power. Color: Black, Condition: New. Listed at 33.99 USD. Both bottom and back of base is magnetic. On/Off Magnet Holding System Base On/off switch 176 lbs. Magnet has an On/Off switch which easily and quickly engages / releases magnet. Magnet has an On/Off switch which easily and quickly engages / releases magnet.