Red Line / syringe

SYRINGE
Unchanged using way! Changed result! The syringe is designed for the purpose of reducing the repeated use of syringes. When you press the rear cover of the plunger, the sharp inside of the rear cover moves forward to pierce the thin-wall. So the red liquid in the end flows into the internal space of the hollow plunger. Then the red liquid becomes an apparent red line to remind people that this syringe has been used.