Medeco identification

[.45cal]

How can you tell what kind of Medeco cylinder you have? Mine has very few markings on it and I was curious.

[MBI]

Here is a thread by Squelchtone with some pics of Medeco cylinder faces. It should answer your question.
viewtopic.php?t=36258

If it says "Medeco" and little else, it's probably an original cylinder.
If it says "Medeco" and has a circle on it bisected by a vertical line that is slightly off center, it's a Biaxial.
If it says "Medeco" and "m3" on it then it's an M3 cylinder.
If it says "Medeco" and "m3B" then it's a BiLevel cylinder.

[.45cal]

so mine is a Biaxial UL 51s thank you for you help I just picked it for the first time a few weeks ago so I was wondering how proud of myself I should be

[Eyes_Only]

You should be very very proud. Even if you just picked a classic medeco that is still a major accomplishment.