Used in conjunction with the MM340 Standard Mount, these MantelMount paintable covers hide the wall surface mounting hardware associated with the mounts wall plates.
MantelMount Sound Bar Adapter
The MantelMount SBXL Sound Bar Adapter accommodates more sound bars than the bracket that comes standard with the MM540, MM700, MM750 and MM860 in that its compatible with wider, taller or smaller sound bars. It also accommodates mounting a 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. The MantelMount SBXL consists of two universal sound bar brackets that fit nearly all flat panel TVs and sound bar models. 
Mounting Information - If mounting the SBXL underneath the bottom of the television, the SBXL mounting holes must be a minimum of 2.5" from the bottom of the sound bar or else you may have to forego installing the MantelMount pull down handle.
Using with MM700/750 - If you have or are ordering the MM700/750 Pro Mounts, you would only need this accessory if the mounting holes on your sound bar are  wider than 29” apart or more than 5” tall, OR if you want to mount your sound bar ABOVE your television. 
Features
Two universal sound bar brackets compatible with most flat and curved screen TVs.
It can accommodate larger sound bars that contain wider than normal spacing between mounting holes.
Accommodates sound bar placement below OR above the TV. 
Maximum load of 20 pounds.
A second person will be required to assist with installation.
The SBXL can be mounted either above or below the television.