The primary purpose of the shipping closure is to protect the aircraft parts or system from storage caps, covers, plugs and related shipping hardware. These items are commonly used on aircraft engines and associated hardware but may be used elsewhere. Military and commercial customer requirements for the prevention of damage or contamination to stored parts are generally limited to the generic instructions "all openings should be sufficiently covered to prevent the entrance of dust, dirt, moisture or other foreign contaminants". This recommended practice outlines basic minimum parameters for suggested item construction and usage. Additionally this recommended practice provides instruction on how to apply these closures to various openings.