Identify This Part Please!

Not sure anyone clearly answered the guy. It is a power steering pump and you use power steering fluid in it. Many use transmission fluid in them also dex/merc since both are a hydraulic fluid. But recommend sticking with P/S fluid. If it is not leaking do not add one with a stop leak additive in it. If it is leaking best to fix the leak (normally high pressure hose, one without the clamp) than add a stop leak to it.