Zeagle

Zeagle Onyx II (DIN)

A balanced, dry-sealed diaphragm regulator built for cold water, confirming Amazon's "Balanced Nitrox... Environmentally Sealed" listing language against Zeagle's own spec sheet.

Environmentally sealed, cold-water rated

Sealed first stage keeps water and ice crystals out of the internal mechanism, the standard for diving below 50°F/10°C.

Zeagle Onyx II (DIN)
4.1Comparison Score
$549.95
Buy on Amazon
Released2013
First stagediaphragm
BalancedYes
Environmentally sealedYes
Cold-water ratedYes
ConnectionDIN
Max pressure300 bar
HP / LP ports2 / 5
Adjustable 2nd stageYes
Weight1250g
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
  • Balanced diaphragm first stage with a dry environmental seal and heat-exchanging hydro transmitter, positioned by Zeagle specifically for cooler water than the standard Onyx
  • Diver-adjustable inhalation effort knob on the 2nd stage, a step up from the Envoy II's fixed venturi-only design
  • Nitrox ready to 40% O2 out of the box, confirmed by both Zeagle and independent specialist retailers
Cons
  • 1-year service interval, shorter than the 2-year interval Zeagle quotes for the pricier F8
  • No octopus included, the Onyx Octo is a separate purchase
  • Also sold in a Yoke version, confirm the listing matches this DIN spec
Diver community sentiment
Mostly positive

Divers on Scubaboard who own the Onyx II describe it as trouble-free, part of a Zeagle lineup they consider "top of the line," with no problems surfacing across annual inspections and biennial servicing. The main critique is a minor ergonomic gripe: the inhalation- resistance adjustment knob is considered mediocre compared to Zeagle's own F8, and aftermarket upgrade knobs are hard to find due to sizing differences. Instructors on the forum recommend it specifically for cold-water diving, citing the sealed diaphragm first stage and heat-sink second stage. A ScubaLab professional test independently rated breathing and dry-breathing performance very good.

Scubaboard: F8 and Onyx II owner feedbackScubaboard: Onyx II cold-water recommendationScuba Diving Magazine: ScubaLab regulator test

Summarized from public forum discussion (Scubaboard, Reddit, and similar), not a survey we ran ourselves. See the linked threads for the original conversations.

The Onyx II is Zeagle’s cold-water-focused mid-tier regulator, built around a balanced diaphragm first stage with a dry environmental seal and heat exchanger to resist free-flow in chilly water. Amazon markets this specific listing as a “Balanced Nitrox Scuba Diving Regulator Environmentally Sealed,” and that framing checks out against Zeagle’s own spec sheet and independent retailer documentation.