True or False: Divers must confirm the oxygen percentage in enriched air cylinders before setting their dive computers.

The assertion that divers must confirm the oxygen percentage in enriched air cylinders before setting their dive computers is indeed false. While it is recommended to be aware of the oxygen content, particularly when diving with enriched air (also known as nitrox), it is not a strict requirement prior to setting the dive computer.

The dive computer is typically set based on the specific blend of gas being used for the dive. If divers use a specific nitrox mix, it is crucial for them to calibrate their dive computer to the correct oxygen percentage to ensure proper calculations for no-decompression limits and other safety parameters. However, in practice, many divers will verify this information during their pre-dive checks and preparations.

The key takeaway is that while confirming the oxygen percentage is a good practice and enhances safety by allowing proper dive planning, it isn’t mandatory as a rule for setting the dive computer, allowing flexibility in diver preparation as long as the divers remain aware of their gas mix before the dive.