Both share the same 81 × 71 × 38 mm body, the same 260 m / 850 ft depth rating and the same single AA battery, and both work with up to four wireless transmitters. The Perdix 3 adds a bigger 2.4 in AMOLED color screen with 4× the resolution of the Perdix 2, a new Big layout, redesigned menus and 6× faster Bluetooth. Shearwater no longer makes the Perdix 2, so it’s available only while dealer stock lasts.

No. The Perdix 3 is a complete dive computer on its own. Air integration is optional: add a Swift or Swift GPS transmitter now or later, and the Perdix 3 can read up to four at once.

Both send your tank pressure to the Perdix 3. The Swift GPS also records your entry and exit coordinates, so each dive shows on a map in the Dive Shearwater app. Its battery lasts up to 100 one-hour dives.

A single AA. Shearwater rates it at up to 60 hours on a 1.5 V lithium (one is included), up to 40 hours on alkaline and up to 80 hours on a 3.6 V Saft.

Yes, the existing Perdix straps, protective cases and screen protectors fit the Perdix 3.