ring-type injector

例句：

1. 1. The ring-type injector is used for precise dosing of drugs.
   环形注射器用于精确给药。
2. 2.In the medical field, ring-type injectors are commonly used for injections.
   在医疗领域，环形注射器常用于注射。
3. 3. The ring-type injector is easy to use and requires minimal training to operate.
   环形注射器使用方便，操作起来也不需要太多的培训。