Not sure what the arrow points to in the photo. If you mean the metal cylinder that is about the size of an empty toilet paper roll then that is the accumulator receiver drier. Its mission in life is to collect moisture and tiny debris. It is practically generic and should be replaced (IMO) whenever the refrigerant lines are opened. About $15.
that's weird the manuals ive looked at today pointed that it was located on the side of the condenser???? I just bought the accumulator today to change it out when I recharge my AC and now looking at it after you stated where its at , how the hell do you get it out in the open to change out filter? its in there tight.