Please help me understand the specs

[Red2x4]

So I'm looking at the UTG 3-12x44 30mm scope. Is my understanding correct?

This scope has a magnification from 3 to 12x.
It has 44mm objective lens.

What is the last number, 30mm, describing?

Thanks for your help.

 

[shutik]

It describes tube diameter. Scope rings of this diameter will fit.

 

[Red2x4]

thanks so much!