Is there anyway to figure out what kind of skimmer you have?

So when I got my tank 3 or so years ago it was a full setup. It came with almost everything including a skimmer. We were very new to saltwater and didn't think to ask what kind of skimmer it was. It has been very irritating resently because I can't find anything that tells me what kind it is. Do skimmers ever have a brand name or a number or something that can tell me what brand it is? I don't even know what size tank it is rated for! I just want to know what kind it is so I can read up on it! Grrr!!! Please help! Thanks!