Here's what Genzler say about the Mounting Bracket:
The MG-350-CRADLE is an aluminum “u” shaped hidden bracket that is designed to attach the Magellan 350 amplifier to the Bass Array™10-2 cabinet. Each BA10-2 cabinet has 6 pre-drilled mounting screws installed into the top which can be easily removed to mount the cradle.
Two thumb-screws are included to secure the amplifier into the cradle. Also, included with each MG-350-CRADLE is a short Speakon speaker cable to the connect the amplifier to the cabinet.