Hello,
Welcome to the forum!
That's a beautiful looking helmet & cover! :bravo: Looks like it is for the 1st Schwere Reiter Regiment, or Chevauleger Regiments 2, 4, 6, 8.
I have a similar helmet w/the spike, white yak hair parade plume, field cover, and carry case.
Thanks for sharing photos with us! =D>
Best Regards,
Alan