Which of the following is NOT required on a scuba cylinder for enriched air nitrox?

In the context of enriched air nitrox, certain markings and labels are essential for ensuring safe use and proper identification of the gas mixture in a scuba cylinder. A key requirement for enriched air cylinders is the presence of a green band marking, which serves as a visual indicator that the cylinder contains nitrox, differentiating it from regular air cylinders. Additionally, a sticker indicating the specific EANx blend and fill date is crucial for divers to understand the gas composition they are using and when it was filled to ensure safe diving practices.

Local laws can also dictate specific markings that must be present on scuba cylinders, ensuring compliance with regulations for safety and identification. However, the diver's photo is not a required marking on the cylinder. This is because the essential identification pertaining to the cylinder's contents and safety considerations relies on the technical markings, rather than personal identification of the diver. Therefore, the absence of a diver's photo as a requirement distinguishes it from the other necessary markings for enriched air nitrox cylinders.