Appearance
Your equipment
The Equipment tab of your profile is your gear list — and it's not just a inventory: the equipment you register here is what you pick from when logging a dive, instead of retyping the same torch every time.

Each item has a type — dive computer, torch, knife, mask and so on — and the date you bought it.
Current and retired
Two tabs. Gear you still dive with sits under Current; when you replace something, retire it rather than deleting it and your old dives keep pointing at the equipment you actually used.
Using it in a dive
When you add a dive, the Personal equipment field offers this list. Anything you pick is attached to that dive.