What are perfume testers?

Testers are original perfumes that come in plain boxes and does not have a cap. It still has the spray and works as well as the one with the standard retail package. Some people may ask, if the perfume does not come with the cap, wouldn’t it stale very quickly? The fact is, no it will not, because the perfume cap is there for aesthetic purpose only. The spray nozzles of perfumes are air tight and it minimizes air from contacting the liquid in the bottle. You can also see many perfumes without a cap in the market, like DKNY Be Delicious, Paco Rabanne 1 Million etc.. Hence, I would recommend testers if it is for own use and never as gifts.