The MantelMount SBXL Sound Bar Adapter accommodates more sound bars than the bracket that comes standard with the MM540, MM700 and MM750 in that its compatible with wider, taller or smaller sound bars. It also accommodates those mounting their sound bar ABOVE the TV, where as the sound bar attachment included with the MM540, MM700 and MM750 only allows for sound bar placement beneath the TV. In additional, this is a great accessory if you want to mount a center channel speaker! The MantelMount SBXL consists of two universal sound bar brackets that fit nearly all flat panel TVs and sound bar models.  Lastly, this is a must buy for anyone looking to pair the MM340 Standard Mount with a sound bar, as the MM340 does not include sound bar attachment.