What is the size of the spike threads on Revel F228Be Speakers?

Hello. What is the size of the spike threads in the F228be's ? I purchased a brand new pair of Revel F228be from an authorized dealer. I need to buy a pair of outriggers here: https://www.nsmt-loudspeakers.com/content/speaker-outriggers 
They asked for the spike threads to make sure they can be attached.
Thanks. BTW, are there outriggers you use or recommend?--

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).
Field Support Engineer
Harman Luxury Audio Group, Lifestyle Division"