B&M short shifter question...

[jaredbzoom]

I have a B&M short throw shifter ( part number # 45071) the box says "will accept the stock knob" but it dont.(huh) ... Anyone know what size knob is needed??
Thanks for the help..

 

[Prodigy]

The MP3 has a different thread pitch....
It'll fit the stock sedan, MSP, and P5 knobs though.