There are several items that are essential when putting together a save-a-dive kit, cylinder valve O-rings, fin straps, buckles, etc. One of the most important items is the spare regulator mouthpiece. Dual-Silicone Comfort-fit Mouthpiece. At Atomic Aquatics, their engineers and award-winning designers are always listening to diver's requests for product upgrades and enhancements. One such request was for a mouthpiece that would be both durable and comfortable. The result is the popular dual-silicone mouthpiece that was introduced with the M1 regulator. Made from two types of silicone material, this mouthpiece is incredibly durable, yet easily one of the most comfortable mouthpieces a diver will ever use. Oh, don't forget the tie wraps to attach it with!