Safety ear plugs serve two main purposes -- to keep loud, harmful sounds out of the ear, or to keep water out of the ear. Some ear plugs are only used for sound. Others can be used for both purposes. It is important to understand what limitations a pair of safety ear plugs may have before purchasing them.
Under most circumstances, safety ear plugs are used in environments where a person may be subjected to constant loud noises. To protect workers, foam ear plugs are standard issue in some industrial settings. These are very cheap to produce, reusable, and are effective at blocking sound.
A good pair of safety ear plugs will be able to reduce sound by at least 20 decibels. While this may not seem like much, it is nearly the difference between a large, heavy truck and a jumbo jet taking off. In other words, an adequate set of safety ear plugs will be able to prevent or significantly reduce the risk of permanent ear injury due to loud noise.
In addition to industrial uses, safety ear plugs can also be used on the shooting range and for snoring relief, though the latter is a secondary usage. Some safety ear plugs may not be suitable or comfortable to sleep in. In such cases, plugs that do not protrude too far from the outer ear are desired for sleeping, because it allows the user to sleep on their side without having to worry about the ear plugs.
In addition to foam ear plugs, other types of ear plugs include silicone ear plugs and custom ear plugs. These types of ear plugs are usually considered to be water ear plugs, as well as sound ear plugs. Safety ear plugs that are custom-made are reusable, as are soft silicone plugs. However, silicone ear plugs may become dirty or break down over time. Even so, silicone ear plugs are cheap enough that they can be replaced after every few uses without ever building a large expenditure. In fact, most silicone safety ear plugs usually come with multiple plugs to a set.
It should be noted that safety ear plugs do not, under normal circumstances, keep all sound out of the ear, though they may diminish the ability to hear significantly. In some cases, this may be a significant hindrance and a reason to consider noise-canceling headphones. As a usage note, there are cases where earplugs, as one word, is used instead of ear plugs.