Mutual Screw & Supply

0.21" CS X 4.975" ID HNBR O-Rings | AS568-351 | Dash 351 | 80 Durometer (7 / Pkg.)

0.21" CS X 4.975" ID HNBR O-Rings | AS568-351 | Dash 351 | 80 Durometer (7 / - Main image
$36.96 $55.16 In stock

HNBR o-rings in AS568-351, 4.975" inner diameter by 0.21" cross-section. Service range -40°F to +300°F (-40°C to +149°C). Also known as HSN, Highly Saturated Nitrile.

Specifications

  • Product type: O-Ring
  • Material: HNBR
  • AS568 dash size: 351
  • Cross-section: 0.21" (5.33 mm)
  • Inner diameter: 4.975" (126.36 mm)
  • Durometer: 80 Shore A
  • Temperature range: -40°F to +300°F (-40°C to +149°C)
  • Measurement type: Imperial
  • Pack quantity: 7 per package
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Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

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Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

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United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

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Customer Reviews (5.0 / 5 · 5 reviews)

Sebastian ★★★★★

Installed these in a hydraulic manifold that sees 275°F peaks and they've held up perfectly so far—no leaks or hardening. The 80 durometer feels just right for the pressure we're running.

Hazel A. ★★★★★

The 0.21" cross-section feels properly beefy when I stretch it over the flange, and the 4.975" ID seats without any wrestling. These HNBR rings handled a 250°F oil bath for a week without losing their shape, which is exactly what I needed for the hydraulic repair.

Benjamin H. ★★★★★

The -40°F low-end rating gives me confidence these will hold up in our unheated warehouse during winter freezes. I've installed a set on a hydraulic cylinder and the 80 durometer feels noticeably stiffer than the standard 70—exactly what I needed for the higher pressure application.