Thanks to all that replied. Here is the answer from Revel support:
" Hello Vlad, Thank you for your inquiry.
The thread designation for the Revel F228Be is M8 x 1.25, with 1.25mm being the thread pitch; both for spikes (external threads) and threaded inserts (internal threads).
Regards,
****
Field Support Engineer
Harman Luxury Audio Group, Lifestyle Division"
" Hello Vlad, Thank you for your inquiry.
The thread designation for the Revel F228Be is M8 x 1.25, with 1.25mm being the thread pitch; both for spikes (external threads) and threaded inserts (internal threads).
Regards,
****
Field Support Engineer
Harman Luxury Audio Group, Lifestyle Division"