Shop by Category

banner banner

Sonar Scuba O-Ring - 112 NBR 90 Duro - Black (10 Pack)



This is a 10-pack of Sonar Scuba O-rings size BS1806/AS568-112, with a hardness durometer of 90, and made from NBR (or Nitrile) Acrylonitrile-Butadine Copolymers which is the preferred choice for most SCUBA diving applications.

This is an O-Ring designed to fit in your tank valve insert to secure the connection between your Yoke first stage and the tank valve itself. It is the replacement O-ring to fit the Faber Yoke Valve and Faber DIN/K Valve Insert, but will also fit many other brands. This is an essential accessory for your Save-A-Dive Kit.

This is the O-ring size typically used at the front and back of the DIN insert used to convert standard DIN valves to INT/Yoke valves. These are the O-rings we commonly use on the San-o-Sub DIN/K valves on Faber steel cylinders.

They are also the standard size DIN O-rings used on the male DIN fitting of many brands of first stage regulators that screws into and seals to the female DIN fitting on the cylinder valve.

We prefer these O-rings with a hardness durometer of 90 over the softer 70 duro ones commonly used.

N90-112 - O-ring Black NBR 90 Duro BS112, 0.487 x 0.103"

Sonar Scuba O-Ring 112-NBR 90 Duro (Black) Features

  • Great Replacement O-Ring for Faber / San-o-Sub Valves
  • Keep a couple in your dive bag for emergency back-up so you never miss a dive again
  • Standard BS112 size
  • Qty 10 are packaged in a resealable plastic bag

BS112 O-Ring Size

BS1806- OD ID CS SCUBA Application Seal
112 11/16" 1/2"
Standard DIN Regulator/Valve
(Nearly all DIN regulators)
Duro: NBR 90

Standard dimensions: CS 0.103" x ID 0.487"
Metric dimensions: CS 2.62 mm x ID 12.37 mm
Nominal fractional dimensions: CS 3/32" x ID 1/2"

NBR O-Ring Material

Acrylonitrile-Butadine Copolymers (NBR or Nitrile)
Most O-rings used in SCUBA are made from Nitrile, a hydrocarbon-based synthetic rubber. Nitrile offers excellent resistance to many oils and acids and has good physical properties. However, Nitrile is not a very oxygen resistant material and is not considered oxygen compatible. Nitrile is also often referred to as Buna-N.

Colour: Black

If you're using you cylinder for Nitrox and oxygen application, you should consider using our Sonar Scuba O-Ring - 112 Viton/FPM 75 Duro - Brown (5 Pack) O-rings.

Tech Tip:
SCUBA Regulator DIN Connector O-ring Sizes

The ISO 12209 standard specification for dimensions of the O-ring groove in the nose of the 232 bar and 300 bar DIN connectors for compressed air has an inside dimension of 12 mm and an outside dimension of 17 mm. In 2003, the standard depth for the groove was revised from the original 1.9 mm to a slightly deeper 2 mm. The specification for the sealing O-ring itself is an inside diameter of 11.2 mm with a cross-section of 2.65 mm. From what we have been able to determine, not all SCUBA regulator manufacturers seem to use the current standard groove and O-ring in the universal DIN fittings found on their first stages.

The sealing O-ring in the nose of the DIN connector groove we find on most SCUBA regulator first stages is commonly an SAE AS568 and BS ISO 3601 imperial standard 112 size that is equivalent to 12.37 X 2.62 metric dimensions. In the case of a few regulators (notably Apeks, Atomic, and ScubaPro brands) their groove better accepts the next smaller 111 size O-ring that is equivalent to 10.77 X 2.62 metric dimensions. Both the 112 and 111 size O-rings are very common sizes available in a variety of choices for material and durometer.

The groove in the Cressi and Poseidon brand regulator DIN connectors measures closest to the original standard, best accepting a BS ISO 3601 metric size O-ring with 11.3 X 2.4 dimensions for which there is no imperial standard equivalent. The M2.4X11.3 size O-ring is uncommon, especially in a material suitable for use with Nitrox. (FYI, the O-ring in Yoke K-valves is easy, it is always an 014 size.)

Compared to the 111 size, the M2.4X11.3 size has a slightly smaller cross-section and slightly larger diameter with a good fit for the O-ring groove of the DIN connectors on Cressi and Poseidon regulators. Because of availability, most Nitrox and technical divers make do with a 111 size O-ring for their Cressi and Poseidon regulators, but the 111 is not as good a fit for the connector of those two brands.

In the European Union nations, the EN 144-3:2003 standard requires a valve outlet known as M26x2 to be used on dive cylinders containing oxygen or Nitrox mixtures with greater than 22% oxygen. The M26x2 outlet is similar in appearance but slightly larger than the standard DIN outlet, and thus incompatible with the standard DIN connector found on SCUBA regulators. The purpose of this incompatible valve outlet is to force the dedication of cylinders, regulators and fill stations to Nitrox use. The sealing O-ring in the nose of the M26x2 connector is 13.9 X 2.6 metric dimensions, equivalent to the 113 size. The M26x2 outlet and connector for Nitrox and oxygen is very rarely seen outside the EU.

(12/20 LRB)

The Scuba Doctor Dive Shop Logo
Connect with us on Facebook - scubadoctor  View our YouTube Channel - ScubaDoctorRye  Follow us on Instagram  View us on Pinterest - scubadoctor  Follow us on Twitter - @scubadoctor
The Scuba Doctor Australia
Boon Wurrung Country
1/49 Peninsula Ave
Rye Victoria 3941, Australia
Commonwealth Coat of Arms
We accept Purchase Orders from Government Departments & Schools
P +613 5985 1700
Opening Hours
Shop by Category
Copyright © 2005-2024 by The Scuba Doctor Australia, ABN 88 116 755 170. All rights reserved. tel. +61 3 5985 1700 :: email. :: Web site by it'sTechnical 2022