Mutual Screw & Supply

0.21" CS X 3.975" ID Buna-N Nitrile O-Rings | AS568-345 | Dash 345 | 70 Durometer | Black (100 / Pkg.)

0.21" CS X 3.975" ID Buna-N Nitrile O-Rings | AS568-345 | Dash 345 | 70 - Main image
$36.38 $58.67 In stock

Buna-N Nitrile o-rings in AS568-345, 3.975" inner diameter by 0.21" 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: 345
  • Cross-section: 0.21" (5.33 mm)
  • Inner diameter: 3.975" (100.97 mm)
  • Durometer: 70 Shore A
  • Color: Black
  • Temperature range: -40°F to +250°F (-40°C to +121°C)
  • Measurement type: Imperial
  • Pack quantity: 100 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 (4.8 / 5 · 5 reviews)

Emily ★★★★★

The 3.975" inner diameter fit perfectly on my hydraulic cylinder bore, and the 70 durometer seals without needing excessive force. I've used these in temps down to -20°F without any hardening or cracking, which the -40°F rating gave me confidence about. Solid purchase for the price.

George ★★★★★

The 70 durometer is just right for the hydraulic seal I rebuilt — not too stiff, not too soft. They slid right into the groove and held pressure on the first test. No leaks so far.

Miles ★★★★★

These are exactly the size I needed for a hydraulic ram rebuild, and the 70 durometer feels firm yet flexible enough to seat perfectly. The 3.975" inner diameter fit snugly without forcing, and the whole pack of 100 saved me from having to hunt down singles.