Buoyancy Compensator: The Buoyancy Compensator (BC) is also called a BCD (Buoyancy Control Device). A BC is an inflatable vest we wear that allows us to control our buoyancy (floating and sinking) underwater. (A BC allows us to become neutrally buoyant underwater.) To control our buoyancy we can add or release air from the BC. The BC includes a special adjustable band that attaches to our SCUBA air tank and holds our air tank on our back. Required Features Proper Fit: BCs should not be too loose or too tight. When you inflate your BC the vest expands and if it is too tight it can be uncomfortably tight. BCs come in different sizes and can be further fitted with adjustable straps. Low Pressure Inflator/Deflator: The inflator allows us to add air from our SCUBA air tank using regulator to the BC at touch of a button. The deflator allows us release air from the BC by pressing another button. (NOTE: On Mrs. Brown's new, high-tech AQUA LUNG® BC both the inflation and deflation are easily controled by a single lever, not separate buttons.) Over-Pressure Relief Valve: This BC valve lets air out of the BC automatically so it won’t pop like a balloon if the BC is accidentally overinflated. AQUA LUNG/Sea Quest® Pro QD i3 BC The BC Mr. Brown uses is a Aqua Lung/Sea Quest® Pro QD i3 BC. The Pro QD i3 is best BC ever built by Aqua Lung®.  It a jacket style BC. This BC has lots of special features that make it more comfortable, safer, and easier to use. Special Pro QD i3 BC Features i3™Buoyancy Control System: A simple level on the side of the BC that allows us to inflate or deflate our BC quickly and easily. Integrated Weight System: Instead of having to wear a separate weight belt with lead weight this BC has pockets for weights built into the BC! This eliminates a separate weight belt! Mr. Brown finds this a more comfortable way to wear his weight. Instead of the hard, uncomforable blocks of lead worn on weight belt Mr. Brown uses weight bags containing tiny lead balls that are soft and comfortable to wear. Cummerbund Waistband: This wide Velcro waistband is easily adjusted for a perfect fit and provides more comfort around the waist. Pockets: Three zippered pockets allow Mrs. Brown to carry things without having to hold them in her hands. One special hidden pocket on the left side is a large pull-down pocket that expands to hold larger items. D-Rings: Four stainless steel D-Rings provide places to clip diving accessories to free our hands while diving. Dive Knife Attachment: Dive Knife attachment points on BC allow a Dive Knife to be fastened to the BC in a convenient, easily reached location. df Octopus Pocket: This is not a pocket for your pet octopus! This is a pocket for your alernate air source regulator, also called an "octopus"! This is great to have since it keeps the octopus handy for emergency use. Hidden Oral Inflator: All other BCs have a large hose dangling on the left front of the BC for inflation/deflation. The i3 System eliminates this hose, but if there is no air left in your air tank to inflate the BC the hidden pull down oral inflator can be used.