Generally divided into cork plug and synthetic plug (plastic plug, polymer plug).
Cork stoppers are made from the bark of cork oak trees (note, not oak, oak barrels are made of oak, it has nothing to do with stoppers). Synthetic stoppers are made of polymer artificial materials and are plastic foamed products. Cork cork can be divided into natural cork (that is, the whole is one), aggregate cork (which looks like a grain of sticky), patch cork (the middle is a grain of cork, two complete pieces of cork on both sides). There are several kinds of polymer plugs, mainly according to the different plastic materials. If you want to say good plug, the best is natural cork plug, which other, according to the workmanship, materials, technology and determine the quality, is not absolutely good or bad.