These are commonly requested O-Rings for the Shearwater Research branded dive computers and transmitters. The O-Rings are sizes, durometers, and materials that are widely available in generic versions, but the OEM O-Rings are supplied to us directly from the Shearwater factory. The O-Ring color may vary and is not significant to the application.

• Perdix (all models), Petrel (all models), and Original NERD Dive Computers - The Perdix battery compartment cap requires two of this O-ring. The Petrel and original NERD (aka NERD 1) battery compartment cap requires one O-Ring. These OEM O-Rings are AS568-112 size, Shore A 70 durometer, NBR (aka Nitrile, aka Buna-N). Sold as a set of two. (This O-Ring size is identical to that commonly used in the nose of many DIN regulator fittings.)
• Swift Transmitter Body - The Swift transmitter battery is under the body housing, which must be removed to access the battery. Shearwater specifies a Metric size for this OEM O-Ring as 24 X 1.5mm, Shore A 70 durometer, NBR (aka Nitrile, aka Buna-N). The Swift transmitter body requires two O-Rings; sold as a set of two. (This O-Ring size is not commonly seen in SCUBA applications.)
• Transmitter High Pressure Fitting - Both the Legacy and Swift transmitter high pressure fitting that screws into the first stage HP port requires a standard first stage HP port O-Ring. Shearwater specifies the ISO version size of this OEM O-Ring as AS568-904, Shore A 75 durometer, oxygen compatible. The transmitter high-pressure fitting requires one O-Ring; sold each. (The widely available Imperial #012 size is virtually identical to the Metric #904 size and Shearwater has confirmed to us that our stock AS568-012, Shore A 90 fluorocarbon elastomer (aka FKM, aka FPM) O-ring will also work equally well in this application. )
• Legacy Transmitter Battery Door - What Shearwater originally sold and now calls the "legacy" transmitter was manufactured by Pelagic Pressure Systems under Aqualung, Aeris, Hollis, Oceanic, Shearwater, Sherwood, and Tusa brand names. The battery is under a battery compartment cap on the end of the transmitter. The legacy transmitter battery compartment cap O-Ring is AS568-016 size, Shore A 70 durometer, NBR (aka Nitrile, aka Buna-N) and requires one O-Ring.

Shearwater recommends o-rings be lightly lubricated prior to installation, see the above Product Attachments tab for installation guidelines. Shearwater tells us that none of these O-Rings require routine periodic replacement under normal circumstances, with exception of the HP port O-Ring if the transmitter is frequently removed from the regulator first stage. FYI, both the Legacy and Swift model transmitters use a widely available standard CR2 size 3.0v lithium battery.

The NERD 2, Teric, Tern, Tern TX, and Peregrine model dive computers have rechargeable batteries that are not user changeable, and thus do not have an o-ring that requires user replacement. The long discontinued Predator and Pursuit model dive computers have a battery compartment cap which requires one o-ring that Shearwater specifies as 3/4-inch x 3/32-inch (which is the same as the AS568-113 standard), Shore A 70 durometer, NBR (aka Nitrile, aka Buna-N) and no longer available OEM from Shearwater although #113 size is widely available from other sources.