This is mine (just like the one my coworker has) and in a pinch I'd say it's 4.5 X 3 and comes with a lovely red box.

I'm keeping mine not out of company loyalty, but for what the whole airline experience had done for me -

Wow - just realized that the Ebay piece is from the same aircraft as my own... Hell, I might have to sign up a Paypal account to get it and have bookends!