ISO 21533:2003规定了可重复使用的针筒注射器的要求和测试方法。 它规定了仅使用ISO公制螺纹尺寸的牙科针筒注射器的要求，并且仅用于内窥镜注射。然而，在一个翔实的附件中考虑了英制螺纹尺寸

ISO 21533:2003 specifies requirements and test methods for reusable cartridge syringes intended for intraligamentary injections. It specifies requirements for dental cartridge syringes only with ISO metric thread sizes, and only intended for intraligamentary injections. However, imperial thread sizes are considered in an informative annex.