What branch of the military uses black uniforms?

I went to an event (non military) and two people had black military uniforms on. No jackets, black pants, black button up shirt with ensignia and one with a cadet hat the other with a beret. Is this an actual branch or a special costume. Also where can I get it? The ultimate deliverable for this question is a link to a place where I can buy the black uniform.|||That could only be the U.S. Navy. Of course...according to Big Navy our uniforms are really, really, really dark navy blue. But those uniforms are typically called Johnny Cash's after the man in black himself.|||The police and even fire department do have military style dress clothes. Maybe they were from one of those departments.|||hard to tell without even knowing witch country because each army has his proper traditions about uniforms.


But in many army's black is the color used by the armor so perhaps they where from a tank unit|||ALL BRANCHES OF THE US ARMED FORCES USE BLACK BDU UNIFORM FOR NIGHT COVERT OPERATIONS|||Try Lawrence Corner in London - they sell all sorts of military kit. Black uniforms? only in French riot Police and the Russian Spetznaz maybe lots of obscure ones around!