Header_bg desktop only

Hello,
I try to have 2 slightly different modules on Header_bg position on desktop and mobile.
I duplicated the module and put "onlymobile" suffixe for the module for mobile.
- But to avoid to have both modules showing on the mobile what suffixe should I put on the one for desktop ?
- Any specific suffix existalso to have one specified for a tablet ?
Thanks in advance for your good support !
Gilles

Please check this documentation:
https://www.gavick.com/documentation/jo ... let-layout

Thanks for the link.
I've checked the "nomobile" class suffixe, but it seems this suffixe doesn't work for 'header_bg' position. I can't get it removed from mobile display using it.

Could you please post an url to your site?

http://diim.org

I see only one module there. Could you please publish both?