There are two main types of belly needles in common use: 1. Insulin injected through the belly:The main role of insulin is to treat type 1 diabetes, or type 2 diabetes that is not easily controlled by oral medication, or other complications or combined types of diabetes. These diseases usually need to be treated with insulin on time and in the right amount. The belly needle of insulin can penetrate the epidermis and inject directly into the fat layer of the abdominal cavity, which helps the release and absorption of insulin. The insulin can be injected directly into the fatty layer of the abdominal cavity through the epidermis, which helps the release and absorption of insulin.