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Black rectangular Buna-N O-rings in a pack of 25

Zoro Select

Zoro Select Buna-N O-Ring Dash 137 PK25

SKU CH-TDWF-6GMXZ

Pack of 25 Buna-N O-rings with rectangular cross-section, dash 137, 70A durometer, temperature range -40 to 250°F

  • Buna-N material resists oils and fuels across a -40 °F to 250 °F range
  • Medium-hard 70A durometer balances seal compression with extrusion resistance
  • Rectangular cross-section profile improves groove retention over standard round rings
  • Pack of 25 dash-137 rings covers multiple maintenance tasks in one order
  • Black colour allows quick visual inspection for wear or contamination

Zoro Select Buna-N O-Ring Dash 137 PK25

This pack contains 25 rectangular-profile O-rings made from Buna-N rubber with a 70A durometer rating. They are designed for static sealing applications where a medium-hard material is required. The rings are black in colour and operate across a temperature range of -40 to 250 degrees Fahrenheit. They are not FDA compliant and are metal detectable but not X-ray detectable.

Rectangular cross-section and material properties

Each ring has a nominal inside diameter of 2 1/16 inches and a nominal width of 3/32 inches. Actual dimensions measure 2 inches inside diameter, 0.103 inches width and 2.256 inches outside diameter. The square profile seats differently than round cord, requiring a matching rectangular groove for proper compression. Buna-N offers good resistance to oils and fuels but degrades in ozone or strong acid environments.

Verify groove dimensions and fluid compatibility

Confirm that your hardware uses a Dash 137 rectangular groove measuring 2 inches by 0.103 inches before ordering. Round-groove housings will not seal correctly with this square profile. Ensure the operating fluid is compatible with Buna-N and that temperatures stay within the stated range. This product is not suitable for applications requiring FDA compliance or X-ray detection.

How it compares

Measured against everything we stock in Threadlockers & Sealants, at today’s prices. Recalculated every night.

Price $8.99
Cheaper than about 90% of the 147 comparable items (median $11.99).

Specifications

Product
Brand nameZORO SELECT

Questions about this item

What does the 70A durometer rating mean for the seal's hardness?

The 70A durometer indicates a medium-hard Buna-N material that resists extrusion under pressure while maintaining enough flexibility to seal effectively in static applications.

What are the actual inside and outside diameters for Dash 137?

The actual inside diameter is 2 in and the actual outside diameter is 2.256 in, giving a rectangular cross section with a width of 0.103 in.

How should these O-rings be seated in the groove to avoid leaks?

Lubricate the ring with compatible grease, stretch it evenly over the gland without twisting, and ensure the rectangular cross section sits flat against both groove walls.

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