Poseidon

Poseidon Xstream (DIN)

A US Navy-approved, 200m-certified diaphragm reg built around a proprietary rolling-diaphragm ball valve instead of a traditional sealed chamber.

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Released—
First stagediaphragm
BalancedYes
Environmentally sealedNo
Cold-water ratedYes
ConnectionDIN
Max pressure—
HP / LP ports2 / 5
Adjustable 2nd stageNo
Weight—
Nitrox-ready (EAN40)Yes
Octo includedNo

"HP / LP ports" is the number of high-pressure and low-pressure ports on the first stage, which caps how many accessories (transmitter, SPG, inflator, second second-stage) you can run at once.

Pros
  • Certified to 200m/656ft and one of only two regulators approved by the US Navy for cold-water use
  • Automatic Inhalation Control and Automatic Venturi Assist mean no manual knobs to fumble with mid-dive
  • Approved for use under ice down to -1.6°C/29°F on Poseidon's built-in Thermo Dynamic Anti-freeze (TDA) system, with no maintenance required
Cons
  • No manual second-stage adjustment for divers who prefer to fine-tune breathing resistance themselves
  • Not environmentally sealed in the traditional sense, it relies on TDA anti-freeze tech instead of a sealed/silicone-filled chamber
  • Poseidon's dive-shop-oriented distribution means parts and service network is smaller than the major brands

The Xstream is Poseidon’s technical/cold-water-certified diaphragm reg, built around a patented ball-valve design the company says cuts potential failure points versus conventional first stages. It’s a niche pick outside Poseidon’s core Nordic and tech-diving following, but it has a genuine following among divers who want automatic, no-fuss breathing performance at depth.