Square O-Rings

Square rings, or Kantseals®, are an alternative for O-rings in axial static applications. Square rings have high sealing capacity and shape stability and are therefore very resistant to extrusion, high pressures and vibrations. Keep in mind that O-rings generally provide a more positive seal because the circular cross-section allow for more concentrated unit loading.

Suitable for

  • Static applications at pressures up to 50 MPa.

Not suitable for

  • Dynamic applications.
  • Applications with a low closing force.


  1. High extrusion resistance.
  2. Dimensionally stable under pressure.
  3. Stable sealing solution with high resistance to rolling during assembly.

How do Square-Rings work?

A Square ring is an elastic part placed between two parts and then squeezed to fill up the gap between the two parts. After installation the ring is  slightly compressed to seal at low pressures. When a square o-ring is pressurised, it’s forced to “flow” within the groove toward the clearance gap.  In comparison to O-rings, the square shape allows the sealing solution to be exposed to higher pressures without the use of a Back-Up ring.

Technical Specifications

Movement type


Available sizes

Any size available upon request.

Hardness range

70 +/-5 Shore (90 Shore for high pressures)

Temperature range

NBR:      -40° to +108° C

EPDM:   -55° to +155° C

FKM:      -25° to +204° C

Pressure range

≤ 500 bar

Available materials


Available compliances

KTW, USP, NSF 51 61, WRC, WRAS, FDA, R67 01

Available standards

AS 568A, DIN 3701, BS 1806/ BS 4518, JIS B2401, JIS NFT47-501, SMS 1568 en ISO 3601.

Common Square Ring types

Type Nitrile (NBR)

NBR Square Rings have good resistance to minerla oils, greases and water up to 100 °C. NBR is not compatible with most solvents, strong acids, fuels with high aromatic content and ozone/weathering. 


EPDM Square Rings have good resistance to hot water, hydraulic fluids, silicone oils and silicone greases. EPDM is not compatible with mineral oils, mineral greases and hydrocarbons. 

Type Viton® FKM

FKM Square Rings have excellent resistance to most chemicals, mineral oils, greases, fuels, ozone and aromatic hydrocarbons. FKM is not compatible with organic acids that have low molecular weight and glycol based brake fluids. 

Alternatives for square rings

Better sealing performance?


D-rings are an alternative for Square-rings. A D-ring has the stability advantages an X-ring and the same sealing characteristics as an O-ring.

D-rings ►

Dynamic applications?


X-rings, or Quad rings®, are an alternative for O‐rings. X-rings have four lips and therefore they have at least four sealing surfaces. The benefits are: high stability, space for lubricants between the sealing lips

X-rings ►



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NewDealSeals B.V.

+31 (0) 226 362 233


Energiestraat 2-5, 1749 DN Warmenhuizen, The Netherlands