The SM-UB1 is designed to fit as many bracket mounting ready speakers as possible. The center slots allow for “single center hole” speaker mounting points, such as: PMC 6, Neumann KH 310, DynAudio Core 7, 47, 59 and more.
The side slots are placed every 5mm. And they are 44mm wide on either side of the center slots thus making it fit 2 to 4 bracket mounting speakers with either 4 or 2 of the holes. EVA foam is added to the sides to protect the speakers and prevent and vibration.