Round Base Magnet with hole on center. size from RB40~RB100 for choose. Round Base Magnet with hole on center.size from RB40~RB100 for choose.It is powerful with hole on center.Attach a hook or knob to position or hold inspection equipment,indicator gauges,lamps,signs,antennas and more.Magnet is on one side.All round base are nickel/chrome plated. Round Base Magnetic Pot(RB )