Flexible waterproof casing specifications DN50, DN80, DN150, DN200 and so on, it can be said that there are many kinds of steel pipe on how many kinds of waterproof casing, waterproof casing using the size of the specifications to be determined according to the size of the steel pipe, usually the size of waterproof casing to be larger than the size of steel pipe. In other words, the key basis for the specification of flexible waterproof casing is the type of steel pipe worn.
