At present, many insulins in the market are divided into two specifications: special refill and refill pen. The special refill is disposable, and the refill is given with the injection pen at the time of leaving the factory, it is integrated, and the insulin can be discarded directly after use, and a new insulin can be used. The difference between the refills is that besides buying insulin refills, you also need to buy a matching insulin injection pen, so that each time you take insulin, you must install the insulin pen to inject it, and if the insulin injection is finished, the insulin refill can be discarded and a new insulin can be installed into the insulin pen, which is recyclable. In fact, the difference between the two is that the special charge is disposable; the refill needs a pen, which can be recycled.