onza trials seatpost diameter?

what is it?

Seatpost: 27.2x350mm, black, reinforced aluminium seatpost.


verner caliper

dude just go down to bunnings or sumthin and buy a cheap vener caliper
its a measuring device for tubular objects

Or could have just posted here, got the answer that swarbrim provided, and not wasted money on a tool that he’d most likely use once.