For this  safety retractable syringe , After use, the needle will be retractable to the barrel and the Plunger will be locked, so it is so safety after use. 

1) A protection to nurse and safety for patient 

2) Guaranteed single use, prevents infection from re-used needles, prevents needle-stick 
Injuries 

3) Provides a high level of protection for healthcare professionals Packing: PE packing or blister