DPA Microphones DUA0350 - Floor Base with Shock Mount for 4097 Microphone250 mm (9. 8 in) diameter floor base with a strong powder painted matte black surface. It has three rubber feet, which ensures stable placement of the microphone stand on any surface. The DUA0250 Floor Base has an integrated shock mount solution: the thread screw holding the Stand Extension and Active Boom Pole. This unique design allows for a long stage microphone boom pole that does not swing, but rapidly stabilizes itself after being positioned.