Disclosed are an air conditioning system with two compressors and a method for operating the same, so as to variably change a compression capacity of a refrigerant according to the variation of cooling load. The earplugs are formed from an extrusion of a maximum diameter of about 12 mm and with narrow locations spaced apart by about 1 to 5 cm to separate the extrusion into a chain of at least ten earplugs, where the last earplug of the chain of earplugs formed by the extrusion can be cut from the rest of the chain for insertion into a person’s ear canal. It is also provided with a bookmark managing server being connected to the Internet and having a bookmark information list providing shared bookmark information which can perform a bookmark function even when the user is using a plurality of types of the terminals.