Mutual Screw & Supply

0.139" CS X 5.109" ID Buna-N Nitrile O-Rings | AS568-251 | Dash 251 | 70 Durometer | Black (80 / Pkg.)

0.139" CS X 5.109" ID Buna-N Nitrile O-Rings | AS568-251 | Dash 251 | 70 - Main image
$34.17 $51 In stock

Buna-N Nitrile o-rings in AS568-251, 5.109" inner diameter by 0.139" cross-section. Service range -40°F to +250°F (-40°C to +121°C). Also known as NBR, Buna-N, Chemigum, Hycar, Perbunan.

Specifications

  • Product type: O-Ring
  • Material: Buna-N Nitrile
  • AS568 dash size: 251
  • Cross-section: 0.139" (3.53 mm)
  • Inner diameter: 5.109" (129.77 mm)
  • Durometer: 70 Shore A
  • Color: Black
  • Temperature range: -40°F to +250°F (-40°C to +121°C)
  • Measurement type: Imperial
  • Pack quantity: 80 per package
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Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

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Delivery costs

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Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

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Returning an item

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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 (4.8 / 5 · 5 reviews)

Elizabeth P. ★★★★★

The 70 durometer feels just right—firm enough to seal my hydraulic fitting without being a struggle to install. Fits the groove perfectly and the black material looks clean and professional.

Sofia ★★★★★

Used one of these as a replacement for an old hydraulic cylinder seal, and the 70 durometer felt just right for the pressure. The -40°F to 250°F range gives me peace of mind for our outdoor equipment. Fit perfectly on the first try.

Zoe ★★★★★

I replaced a worn-out seal in a pneumatic cylinder with this 5.109" o-ring, and the snug fit on the grove was perfect. The 70 durometer material feels durable but not too stiff. It’s held up well under constant pressure so far.