<p>The most common regulator mouthpiece has two small, untextured tabs which the diver bites down on to keep the regulator in his mouth. These mouthpieces fit easily inside most divers&#39; mouths, and smaller versions are available for <a href="https://www.thoughtco.com/minimum-age-for-scuba-diving-2963215" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1">child divers</a>. Some divers complain that they must bite down hard on standard mouthpieces to keep them in place, while divers who dislike using bulky mouthpieces may prefer this simple style.</p><p>Long bite mouthpieces have long bite tabs that extend far into a diver&#39;s mouth. This distributes the pressure from the mouthpiece across more of the diver&#39;s teeth. Most divers find long bite mouthpieces very comfortable, however divers with short mouths may find this style of mouthpiece annoying. (I have a narrow mouth and am still comfortable using long bite mouthpieces). My favorite brand of long bite mouthpiece is made by <a href="https://www.amazon.com/Trident-Long-Bite-Mouthpiece/dp/B002KTD6VE" data-component="amazon" data-source="affiliate" data-type="externalLink" data-ordinal="1" rel="nofollow">Trident</a>, and molded of very soft, flexible silicon.</p><p>Bridged mouthpieces have an arched piece of silicon connecting the bite tabs. This silicon &#34;bridge&#34; sits against the roof of the diver&#39;s mouth, locking the mouthpiece in place and reducing the effort required to keep the mouthpiece in place. Some divers love this mouthpiece style, and claim it reduces jaw fatigue. Other divers hate the feeling of the silicon pressing against the roof of their mouths. As a diver with a narrow mouth, I find that bridged mouthpieces do not sit smoothly against the roof of my mouth, and tend to cause a blister. One example of a bridged mouthpiece is the <a href="http://www.leisurepro.com/Catalog.aspx?op&#61;ItemDisplay&amp;ProductID&#61;UDRCBM&amp;Page&#61;1&amp;Term&#61;mouthpiece&amp;Hit&#61;1" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1" rel="nofollow">Aqua Lung Comfo-Bite Mouthpiece®</a>.</p>Divers who dislike the feeling of a mouth full of silicon are likely to enjoy these minimalist mouthpieces. The mouthpieces have small, triangular tabs that fit into the middle of a diver&#39;s mouth without placing any pressure on his front teeth. Some divers dislike these mouthpieces because of the relatively small surface of the bite tabs, and the fact that the pressure from the regulator mouthpiece is concentrated on only a few teeth. These mouthpieces come standard on some styles of Cressi regulators.These mouthpieces are designed with &#34;winged&#34; bite tabs that project above and below the biting surface. The winged bite tabs help to lock the mouthpiece in place. Most divers will find these mouthpieces comfortable, however some divers find that the bite tab wings rub against their gums. This mouthpiece style comes standard on many Apex regulator second stages.<p>The main feature of these mouthpieces are the raised &#34;cushions&#34; on the bite tabs. Manufacturers claim that these mouthpieces are very durable, and that the cushions create a tabs surface which is easy to hold in place with minimal effort. The key to purchasing this style of mouthpiece is to choose one made of top-quality silicon. Cheap versions of this style are uncomfortably hard. Divers with narrow mouths may find that these mouthpieces are a bit wide and do not conform easily to a narrow mouth shape. One popular version of this style of the <a href="http://www.scubatoys.com/store/detail.asp?PRODUCT_ID&#61;AtomicComfortMouthpiece" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1" rel="nofollow">Atomic Comfort Mouthpiece</a>.</p>Tooth-covering mouthpieces have a thin flap of silicon that projects above and below the mouthpiece and sits in front of the diver&#39;s teeth. This locks the mouthpiece between the diver&#39;s gums and lips, reducing the effort required to keep the mouthpiece in place. If the mouthpiece fits correctly, this style can be very comfortable and quite effective at reducing jaw fatigue. However, divers with sensitive gums may not like this mouthpiece as it may press uncomfortably against the front of a diver&#39;s gums and the inside of his lips. These mouthpieces are also more difficult to insert into a small mouth than lower profile mouthpieces. Tooth-covering mouthpieces are now a standard mouthpiece style for many SCUBAPRO regulators.Moldable mouthpieces allow divers to custom fit a mouthpiece. The diver trims the mouthpiece to the desired length, heats it, and then bites down on it to mold it to his unique dental features. Many divers swear by customizable mouthpieces (the one shown here is a SeaCure® Mouthpiece), and claim they are the most comfortable mouthpieces on the market. However, keep in mind that customizable mouthpieces should not be used on alternate air source regulators, or regulators that are handed off in an emergency to share air with a buddy. The custom mouthpiece may make breathing from the regulator difficult or impossible for another diver.