Avenova is built around a single ingredient: pure hypochlorous acid, a molecule the body makes on its own, formulated here at 0.01 percent with no detergents and no bleach impurities. The spray started life as a prescription product and is now sold over the counter. It comes in glass rather than plastic, a packaging choice the brand made to keep the solution pure.
Most people begin with a single 20ml bottle and add pads later, since the spray can be applied to a clean pad or directly to a closed lid. The complete kit is the shortcut if you are assembling a lid hygiene routine from scratch and want drops in the same order. The three pack and the two pack are simply better value once you know the spray suits you.
The formula is oil free and unscented, which is why it comes up often among people wearing lash extensions and among those who find scented cleansers bothersome. Avenova is a lid and lash hygiene product rather than an eye drop, so it sits alongside whatever drops you already use rather than in place of them. If you are not sure where it fits, your eye care professional can walk you through the order of steps in a daily routine.