You can’t do that but you can select props and click the eraser to erase multiple.
Also, if you want to make a prop/barrier (device) the same size as a new one, you can click the Change Size button, move it to the prop you want to copy the size and shrink it till it’s as big as your chosen prop.
Example:
(Just shrink it a little bit more)
Do note that Gimkit Creative is not meant to work on mobile so there may be issues.
This guide might help:
Length Warning, Click to open dropdown
Hi, Welcome to the forums, @Theo123!
Don’t forget to check out the #new-user-must-read and forum-tips tag.
The Community Made Guides category is also very useful, posts there give you a gist of the rules and mechanics in Gimkit Creative.
While you’re at it, I suggest also reading the
If you need help with anything, just ask!
After all, this is a Community Forum 
!