In comparison with Luer-lok syringe, Luer slip does not have a locking mechanism. In order to join the needle to the syringe the needle is simply pushed onto the tip of the syringe where it fits snugly. In contrast, the needle needs to be twisted onto the Luer-lok syringe to lock it in place. Because of this, Luer slip is used for less viscous medicine injections and vaccinations.
Word origin: from its German medical instrument maker, Hermann Wülfing Luer (18th century)