This is what I caught via youtube. Here's a link for ya. http://www.youtube.com/watch?v=O3bTBcIMVG4
There's a height requirement. For males it's 6' and females it's 5'10". The video states that they come the 3rd week of Basic. If interested, sounds like you put it on your Dream Sheet.... Like I stated, this is all "hear-say." Perhaps there's someone out there who could help ya out.