There are four types of silica gel cartridge adapters, two specifications, which can be differentiated according to length and interface size. They are M15 (short), M15 (long), M21 (short) and M21 (long). They can adapt to various types of specifications to avoid inappropriate products. The long series are mainly used in combination with dispensing valve, and the short series are mainly used for semi-automatic machines. These are clearly used according to the industry Rules.