The Yamaha BMS10A Mic stand adaptor.
Ideal for mounting Yamaha MS101iii speaker as monitor on a standard mic stand
The Yamaha BMS10A adapter mounts loudspeakers of up to 11 pounds to a microphone stand. The BMS10A fits the 5/8 inch, 27-thread standard and comes with a 3/8 inch -16 European thread adapter. The BMS10A comes with two 5mm screws needed for mounting.
The BMS10A also supports MG10/2, MG8/2FX and the STAGEPAS 300 mixer on mic stands. The BMS10A is sold as a single unit.