What is a px in the military?

Excuse me, but could you please clarify what you mean by "px" in the context of the military? Is this a reference to a specific rank, abbreviation, or term used in military jargon? If so, I'd be happy to provide an explanation or context for its meaning, but I would need a bit more information to accurately answer your question. Is there a specific area of the military or type of operation you're referring to?