<a href="//commons.wikimedia.org/wiki/Oxygen" title="Oxygen">Oxygen</a> and <a href="https://en.wikipedia.org/wiki/MAPP_gas" class="extiw" title="w:MAPP gas">MAPP gas</a> compresed gas cylinders with regulators. The high pressure side of the oxygen regulator reads 1,000 <a href="https://en.wikipedia.org/wiki/PSI" class="extiw" title="w:PSI">PSI</a> (69 <a href="https://en.wikipedia.org/wiki/bar_(unit)" class="extiw" title="w:bar (unit)">bar</a>). The tremendous pressure inside the oxygen cylinder (over 2,200 PSI (152 bar) in a full tank) requires <a href="//commons.wikimedia.org/wiki/Extrusion" title="Extrusion">extrusion</a> as a manufacturing process and these tanks may never be welded. The lower pressure MAPP cylinder was welded together and the seam is visible where the yellow and white paint meet.
<a href="https://en.wikipedia.org/wiki/User:Triddle" class="extiw" title="en:User:Triddle">Triddle</a>
28 February 2005 (according to <a href="https://en.wikipedia.org/wiki/Exchangeable_image_file_format" class="extiw" title="en:Exchangeable image file format">Exif</a> data)
<span class="int-own-work" lang="en">Own work</span>