Fx impact shroud

Yes unscrew telescope shroud this one screws directly to the berral

Need some help to identify the threads on the fixed shrouds for Impact.
Should be the same as for the telescopic version, the end closest to the shooter.
And the fixed shroud has the same thread in both endsIt looks like the thread is M26,5 x 1,5 but could this be correct?
Veeery odd thread,

In Canada we only have fixed shroud for every caliber and it is a very good thing.
I dont trust extandable shrouds.