Bolts for Paradigm Studio 20s

Does anyone know what size bolt fits the threaded holes on the bottom of Paradigm Studio 20 v.3s? I have tried a variety, including metric sizes, to no avail.

Did you try sending Paradigm an email?
No, but I find my Paradigm Studio 20 v.3s to be very stable sitting on a pair of made to measure Skylan stands without the need to use the speakers threaded bolt holes.

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