How do I measure thickness of bath screen to replace the seal?

[Celeriacacaca]

There's nothing on the screen to indicate size as in thickness of glass, so just wondering how do I measure it please, or is there another way to tell? TIA.

calipers will be most accurate, but a millimeter ruler should be pretty near.

Actually it's not calipers , it's a micrometer

www.google.co.uk/#q=micrometer

Specialist subject, I know because I often use one to measure my wad of money that buy to let landlords dribble at the thought of having the privilege of smelling yet alone owning

My dog now owns a yacht

callipers is also the correct term here in the UK. I recall you're a yank so your ignorance is excused.

out on day-release again, I see?