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Sonar Scuba O-Ring - 112 Viton/FPM 75 Duro - Brown (5 Pack)



This is a five-pack of Sonar Scuba O-rings size BS1806/AS568-112, with a hardness durometer of 75, and made from FPM/FKM/Viton® Fluorocarbon Elastomers which are the preferred choice for oxygen and nitrox compatibility in 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 prefer to use on the San-o-Sub DIN/K valves on Faber steel cylinders that are being used for Nitrox or Oxygen.

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.

V75-112 - O-ring Brown FPM 75 Duro BS112, 0.487 x 0.103"

Sonar Scuba O-Ring 112 Viton 75 Duro (Brown) Features

  • Viton fluorocarbon elastomer (FKM) oxygen resistant O-rings
  • Preferred Choice For Oxygen And Nitrox Compatibility
  • 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 Size BS112
  • Brown Colour
  • Qty 5 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: FPM 75

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"

FPM O-Ring Material

Fluorocarbon Elastomers (FPM/FKM/Viton®)
O-rings made of FPM/FKM/Viton® have been the preferred choice for oxygen and nitrox compatibility in SCUBA diving applications. FPM/FKM/Viton® is an elastomer with excellent oil and oxygen resistance at high and low temperatures, very good chemical resistance. Even for use with ordinary air, most experts agree that FPM/FKM/Viton® O-rings outperform common Nitrile O-rings.

The Difference between FPM, FKM and Viton®
The terms FPM, FKM and Viton® very often cause confusion and lead to incorrect interpretations. All of these designations actually stand for one single base material: fluoro rubber.

  • FPM is the international abbreviation according to DIN/ISO.
  • FKM is the short form for the fluoroelastomer category according to the American standard ASTM.
  • Viton® is the registered trade mark of DuPont Performance Elastomers.

Colour: Brown

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)

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