Color Change Needles / needles

Nowadays, a lot of places exist infective diseases like AIDS. Some of them spread through body fluids. They are more widely spread recently because doctors inject their patients with used injector needles. It is very unhygienic and sometimes causes infections.
This is a special injector needle with the color-changing plastic packed on its end. The needles not yet used are present green, while the used ones are red. It can help both doctors and patients differentiate used ones from new ones more easily and prevent the disease to spread through injection.