Vararam Intake Grabber bolt size?

[4d6n2]

Hello!
I'm wondering if anyone here knows off the top of their head what size the bolt posts that the wingnut screws on to. I cracked the cover around the posts and I'm going to repair and paint it, and I'm wanting to find some properly sized washers and rubber grommets so I can keep it from happening again.

 

[04fxdwgi]

I'll go out and check mine later, but think it's 1/4" or some metric equivalent of it.