What is a dive slate?

A dive slate is specifically designed as a waterproof writing surface that allows divers to communicate underwater. Communication is critical while diving, especially when visibility is limited or when noise from equipment prevents verbal exchanges. The slate typically consists of a small board made from a durable, waterproof material, often covered with a writing surface that can be used with pencil or grease pencil. This enables divers to convey important messages or notes to their dive partners or to document observations during their underwater exploration.

The other options relate to different aspects of diving, such as measuring depth, buoyancy control, and navigation, but do not accurately describe the primary function and purpose of a dive slate, which is focused on communication.