Middle Atlantic MAG-1/2 Use Middle-Atlantic's 1/2 inches Magnetic Sockets (2-Pack), because nothing is easier than complete accuracy. These 1/2 inches magnetic sockets allow you to get multi-bay rack edges flush with each other while tightening bolts. The heaviness of metal can cause racks to sag as each piece is connected, but these sockets prevent that annoying, and sometimes damaging delay. Middle-Atlantic designs their racks and rack accessories to be exactly what you need.