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Black Buna-N O-ring, 4-3/8 inch ID, 1/4 inch cross-section, pack of five

Zoro Select

Zoro Select Buna-N O-Ring 4-3/8 in ID 1/4 in Width Black PK5

SKU CH-ZHQW-0RB22

Pack of five Buna-N O-rings with 4.3 in inside diameter and 1/4 in nominal width for sealing up to 250 °F

  • Withstands extreme cold to -40 °F for reliable sealing in harsh environments
  • Handles continuous heat up to 250 °F maintaining integrity in high-temp applications
  • FDA-approved Buna-N material ensures safe contact with food and pharmaceutical products
  • Precise 4.3 in actual ID and 0.275 in width deliver consistent, leak-free fit
  • Medium-hard 70A durometer resists extrusion and deformation under pressure

Zoro Select Buna-N O-Ring 4-3/8 in ID

These Buna-N O-rings have a nominal inside diameter of 4 3/8 in and a nominal width of 1/4 in. They come in a pack of five with a durometer rating of 70A. The operating temperature range spans -40 to 250 degrees F. FDA approval makes them suitable for food-contact applications.

Maintenance teams needing inch-series seals

The round cross-section and actual inside diameter of 4.3 in fit standard grooves. Metal-detectable material helps with contamination control in processing lines. Buyers who need X-ray detectable seals should look at other materials. The medium-hard 70A durometer may not suit very low-pressure or dynamic sealing needs.

Dash number 424 identifies the groove size

This dash number corresponds to the nominal 4 3/8 in inside diameter and 1/4 in width. The actual dimensions are 4.3 in inside diameter and 0.275 in width with a 4.9 in outside diameter. Matching the dash number ensures the correct groove fit for the seal.

Highlights

  • Withstands extreme cold to -40 °F for reliable sealing in harsh environments
  • Handles continuous heat up to 250 °F maintaining integrity in high-temp applications
  • FDA-approved Buna-N material ensures safe contact with food and pharmaceutical products
  • Precise 4.3 in actual ID and 0.275 in width deliver consistent, leak-free fit
  • Medium-hard 70A durometer resists extrusion and deformation under pressure

Specifications

BrandZORO SELECT

Questions about this item

What groove dimensions do I need for a 4-3/8 in ID O-ring with 1/4 in nominal width?

The seal has an actual inside diameter of 4.3 in and an actual width of .275 in. Design the gland to match those dimensions and the 70A durometer for proper compression.

Will this Buna-N 70A O-ring withstand the same temperatures as the Viton seals I currently use?

This material is rated from -40 to 250 degrees F. Viton typically handles higher heat, so verify your peak temperature stays within the 250-degree limit before swapping.

How can I confirm the O-ring is seated correctly after installation?

Check that the black Buna-N ring sits evenly in the groove with no visible twist, and that the metal-detectable material is present if your line uses detection equipment.

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