Several model rebreathers use a Shearwater electronics package incorporating CAN bus digital signalling technology. The standard LED HUD that comes with the electronics can be upgraded to a full Shearwater NERD 2 dive computer HUD by unplugging the LED HUD and plugging in the NERD. Shearwater also offers "analog" monitor only versions of the NERD using either a Fischer 103 or AK 4-pin connector.

† NOTE: There are a few models of the NERD 2 that offer DSV mounting hardware specific to the rebreather brand plus a brand logo startup splash screen (JJ and O2ptima; however the models for the rEvo III are only available through rEvo.) The JJ version of the NERD 2 also includes a brand specific fixture for securing the CAN bus connector to the JJ head. In addition, there is a generic model with universal mounting hardware and startup splash screen that is not rebreather brand specific which will work with all brands of rebreather that include the Shearwater DiveCAN technology (Prism2, Tiburon, all others). We also have versions of the NERD 2 that can accept up to three direct analog inputs from oxygen sensors. The two unit specific mounts we offer are special order (about 1 -2 weeks), and the generic universal mount versions are normally stocking items.

The Shearwater NERD 2 is the first technical dive computer with a display mounted on the diver's rebreather mouthpiece. This revolutionary device keeps crucial information in your line-of-sight for the entire dive. Thanks to the Micro LCD display and magnifying lens, the data appears as if displayed on a 25" TV screen 12' away, with no need to focus. If you can watch a TV without glasses, and even if you have a bifocal lens mask for reading gauges, you should have no problem seeing the NERD. The display is unobtrusive as it virtually disappears when you look straight ahead. The numbers are there when you need them at any point during the dive, and out of the way when you don't. The full color display is used to convey additional meaning with the information being displayed. When information is yellow or red, it calls the diver's attention to an unusual value or problem.

During a decompression dive, the NERD 2 provides complete information displays of all required stop times and incorporates the Bühlmann ZHL-16C algorithm, with user configurable Gradient Factors (GF). Gradient Factors allow the diver unique and individual control of their dive computer decompression calculations. An optional PIN upgrade to the Varying Permeability Model (VPM-B and VPM-B/GFS) decompression algorithm is also available (the DCIEM algorithm is not applicable to rebreather modes.) The NERD 2 can provide time-to-surface based on "look ahead" at planned gas switches. Multiple gas definition presets are supported with any combination of oxygen, nitrogen and helium. The NERD 2 will NOT "lockout" after a missed stop or ascent rate violation. After the dive, the NERD 2 communicates via next generation Bluetooth Smart Ready™ with iOS devices such as the iPad and iPhone. In addition to current Shearwater and third party support for Mac and PC desktop applications, users are able to download dives using their iOS devices in conjunction with third party applications. The NERD 2 incorporates a built-in lithium-ion rechargeable battery. Users can expect a minimum of 18 dive hours, on medium brightness, from a fully charged NERD 2 and 5 charges from the charge bank.

The NERD 2 is capable of wirelessly connecting to optional transmitters giving the diver ability to monitor up to four tank pressures. Air integration is optional for all modes, from OC Rec to CC/BO. The tank pressure(s), in PSI or BAR, can be displayed to the customizable slots on the main display screen or accessed through the underlying information screens. Enabling the AI feature causes approximately 10% decrease in battery life.

Included with every NERD2-hardwired from Dive Gear Express are a mounting clamp, recharging clip, charging bank, USB cable, and hardwired cable with connector. The software includes a complete dive log manager, compatible with both MS Windows and MAC OS X, and can be downloaded from Shearwater's website along with the manual. The dive log manager supports log downloads and firmware updates via the Bluetooth wireless interface. An optional VPM-B unlock code enables using the Varying Permeability Model (VPM-B and VPM-B/GFS) algorithm for calculating decompression.