Gauging DOT 3AL3000 SCUBA cylinder neck threads
In response to requests for clarification, from members in the Far East and Australasia, the following guidance is issued for SCUBA cylinders and valves that utilise the ¾" NPSM thread form. ASSET recommends that technicians, involved in the assembly and maintenance of SCUBA cylinders and their valves, use the appropriate, calibrated, thread gauges as a means to ensure that they are both within tolerances and compatible with each other. Additionally, the technician should have received training in their use, as provided in the ASSET Dive Industry Technician’s and Cylinder Tester’s Courses and Manuals.
How to Avoid Isobaric Counter diffusion hits during trimix decompression
Isobaric Counter Diffusion triggered by breathing gas changes is predominantly a problem when carrying out Trimix dives that are deep enough and long enough to generate formal decompression stops that require the use of a hypoxic Trimix. An analysis program embodying these concepts to identify known unsafe ICD gas switching practices and unsafe decompression is made available


A button gauge is commonly used on decompression cylinders. Because a button gauge is typically small in size, reading the values on it can be difficult to read.

Thanks to technology, a scuba regulator can now have an air integrated computer, giving a diver more options for reading diving cylinder pressures. However, scuba regulators with air integrated computers are often backed with standard air pressure gauge.

Mechanical reserve valves are another important part of scuba regulators. In diving, there are cylinder types that use mechanical valves with a reserve lever, which serves to restrict air flow particularly when pressure is below a preset or predetermined amount. These type of mechanical valves are commonly referred to as "J valves." These mechanical valves were named as such because in US diving catalogs, the valves were next the letter "J". Mechanical valves that do not have a reserve lever are referred to as "K valves." J valves in many modern diving equipment have the reserve valve in the open position.