Engraved markings on scuba tanks include which of the following?

• A. Date of hydrostatic test
• B. Serial number
• C. Type of material
• D. All of the above

Answer: (D)

Markings on scuba tanks carry essential safety and maintenance information. The date of hydrostatic test shows when the tank was last tested and when the next test is due, ensuring it stays within required inspection intervals. The serial number provides a unique identity so the tank’s history, inspections, and any recalls can be traced. The type of material tells you what the cylinder is made from, which affects strength, corrosion characteristics, and appropriate handling and testing practices. Because each of these elements is commonly engraved on tanks, all of the above are included.