Products - Computers


Shearwater introduced the Perdix AI richly featured technical diving computer in 2016 priced at $935, and the Peregrine extended range sport diving computer in 2020 priced at $450. They have identical color display screens with very similar core feature sets and operation, but the Peregrine can best be thought of as a value engineered Shearwater dive computer appropriate for Air and Nitrox divers that supports multi-gas planned decompression diving, yet without compromising on quality or ease-of-use.

The Perdix AI is a best-in-class technical dive computer that includes support for Trimix, VPM alternative deco algorithm, wireless air integration, an electronic compass and rebreathers. Compared to the very deep rating of the Perdix design, the Peregrine low profile case design is appropriate for the depth limits of Air and Nitrox divers thus allowing significant cost reduction. Omitting the wireless air integration radio receiver and the electronic compass generates further savings. No need to support mixed gas, VPM and closed-circuit also allows for simplified software. The Perdix is powered with any AA size battery and is user changeable, the Peregrine is powered with an internal rechargeable Li-ion 900mAh battery.

Garmin offers the Descent Mk1 multi-activity smartwatch and dive computer in both a silver/black color (aka "Stainless") version and a gray/blue color (aka "Titanium") version. The silver/black Mk1 version has a stainless steel bezel with black accents and the gray/blue Mk1 version has a titanium bezel with blue accents. All models include the black silicone QuickFit wrist strap set, and some configurations also include a metal link QuickFit "bracelet" style wristband.

They differ in price, leading some to wonder if there is any difference in features or functionality. The body of the device on both versions is the same fiber-reinforced polymer with stainless steel buttons and sapphire crystal lens, yielding the same depth rating. Both versions of the Mk1 have the same electronics with Bluetooth Smart, Wi-Fi and ANT+ connectivity and the same firmware, thus having the same features and functionality.

The Shearwater Research Peregrine dive computer does not have the internal hardware for support of RF transmitters to display the cylinder gas pressure, commonly called wireless air integration (AI). Shearwater tells us they have no plans to add AI to the Peregrine.

Frankly, the Peregrine is a value engineered computer for which the AI feature does not make much sense in that price range because a single transmitter costs almost as much as the computer itself. If the AI feature is a requirement for your diving, we suggest you consider either the Perdix AI or the Teric.

The short answer is you do NOT need the VPM upgrade. The Varying Permeability Model (VPM) is a bubble model based decompression theory that is available on some older models of Shearwater dive computers as an optional alternative to the default Bühlmann GF gas content model used by all Shearwater dive computers (and most other dive computers) to compute no-decompression limits and decompression schedules for dives. There is no expert consensus that VPM is better than Bühlmann, and some recent studies suggest VPM may be worse. If you don't understand the differences and why you would choose one or the other, Dive Gear Express and Shearwater recommends sticking with the factory default of Bühlmann 30/70.

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