The Right Way to Read Scuba Tank Markings

Before going scuba diving, it is critical to understand the basics so that you know what you are doing for your own safety. The exterior of a scuba tank features visible markings. These marks give critical information for your tank.

How to Read the Markings on a Scuba Tank

Photo Credits: Scuba Workshop UK

➖M25 X 2

The Thread Specification is identified by this label. It also specifies the thread style and dimension. It is required to use the right valve with your cylinder.


This label identifies the country in which the cylinder was made. Every nation has its own emblem or abbreviated name.


The name of the Cylinder maker is shown by this marking. There are several reputable brands of diving tanks on the market.

➖P3173V/LUXFER 1234A

Serial digit and cylinder style digit. The manufacturer, in this case, Luxfer, records this number so that the complete production history of your diving tank may be traced.

➖AA6061 T6

This symbol specifies the kind of aluminum used to make the cylinder. It will sometimes be built of aluminum.


This indicates the minimum designed scuba tank wall thickness.


This symbol denotes the scuba cylinder’s empty weight. When the tank is loaded it will be heavier.


This symbol represents the minimum water volume in liters.


This symbol denotes the operating pressure. It indicates the pressure at which the scuba tank should be filled. This amount must be never surpassed.

➖PT348 BAR

This symbol denotes the Test pressure. It indicates the pressure at which the diving tank should be checked. This limit must be never breached.

➖PS287 BAR AT 60 C

This is the assistance pressure, and it represents the force that may build within the scuba tank at the temperature specified; don’t mix it with the operating stress.

➖CE 0038

This is a compliance mark to the Pressure Equipment Directive 97/23/EC that indicates the body identification number.

➖2002 / 2

The date of the test is shown by this marker. It indicates when your cylinder was initially tested, with the year then by the month of the test year imprinted onto the tank in a hoop.


This indication tells who the cylinder was initially designed for.

Frequently Asked Questions

Q: How can I tell if my scuba tank is made of steel or aluminum?

A: If a magnet attaches to it, it’s made of steel. And if it doesn’t, it’s made of aluminum.

Q: How do you calculate a scuba tank’s capacity?

A: Divide the real pressure by the full pressure and multiply by the volume in cubic feet of a full tank to determine the actual volume of a less-than-full tank.

Q: Is the majority of scuba tanks made of steel or aluminum?

A: Aluminum is still generally chosen across the world since it is more cost-effective and easier to keep.

Q: What is the thickness of a scuba tank’s walls?

A: The walls of diving cylinders are typically 2 to 5 mm thick.

Q: Is it true that empty scuba tanks float?

A: Steel scuba tanks never float; they are always negatively buoyant. However, it can be a different case with other materials. Whether a suba tank can float depends on a lot of other factors.

Final Thoughts

It is critical to understand the markings on the scuba tank. It contains all of the information you need to conduct a safe dive. Having competent guidance from your instructor is also essential. Applying all of the safety precautions during the dive will make a significant difference in your underwater life. Before you begin the sport, take the time to understand and study the vital things you need to know.