Just a copy of the description:

…More than 160 international scuba hand signs for underwater communication. For divers and those who start scuba diving!

Improve your communication during scubadiving!

This app has actually three modules:

General hand signals
- Instructions and references
- Problems
- Danger signals
- Questions
- Numbers and units
- Nightdive

Hand signals for marine life
- Sharks and rays
- Reptiles and mammals
- Fishes
- Lower animals
- Freshwater fishes

Funny hand signals

The app displays a photo of the marine animal with every hand sign. You and your dive-buddy will always be speaking about the same thing!

For those not owning an iphone or iphone touch the english printed version of the Dive Signal booklet is coming soon (right now available in german).

Find the frequently used scuba hand signs in this app. Ideal for traveling!

Feel free to take a look on the website: http://www.ok2dive.de