So you have purchased the basics now it is time to move into the accessories. Some accessories are necessities while other are just for fun. I have compiled a list of gear that I have found to be necessary during my dives.

Lights

Of course these are necessary for night dives or for looking into dark crevices but they prove useful during the day as well. White light, such as sunlight, is actually composed of various colors mixed together (red, orange, yellow, green, blue). The colors are absorbed one by one as depth increases starting with red, orange, yellow and so on. Since each color is part of the total light entering the water, less light remains as depth increases and each color is absorbed. For these reasons, deeper water is darker and less colorful. Red, orange, or yellow objects often appear brownish, gray or black. To see true colors, you will need to provide a source of light.

Knives

Diving knives are practical tools, not intended to be, nor should it be, used as a weapon. Knives can be a means to measure, pry, dig, cut and pound under water. Ever fished? You cast your line it gets caught on something and breaks. Most people don't think much about it and go on with their task of catching the big one. Well monofilament line has staying power and will linger until it snags something or someone else. I have run across monofilament line on several occasions, luckily I was never entangled.

Compass

You will learn compass navigation during your certification. Some people never touch one again after they get their C-card. A compass can be very handy when you are shore diving and want to hit a certain ship wreck that is 100 yds. off shore to the north. It is also helpful for getting you back to where you started.

Underwater Slate

Slates are an important communication tool that can carry information regarding your time and depth limits. They can also add another dimension to your hand signals while underwater. Slates come in a variety of styles, some made for the pocket of your BCD, others fit in a pocket, while some are custom-tailored to fit on the back of your instrument console.

Collection Bags

Sooner or later, you'll find or catch some things while diving that you want to keep. It isn't pleasant juggling a handful of objects while trying to operate your equipment. Please keep in mind that taking life from the reef can bring you a hefty fine. Take nothing and leave only bubbles is a common courtesy. The only time I have ever taken out my collection bag is to pick up garbage.

Glow Stick

A chemical light stick usually attached to the tank valve during a night dive so a diver can be seen in the dark by his buddy and other divers. Also called a cyalume stick. A chemical light stick usually attached to the tank valve during a night dive so a diver can be seen in the dark by his buddy and other divers. Also called a cyalume stick.

This information was obtained from the Padi Open Water Diver Manual