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Black Buna-N O-rings, 3.7 in ID, pack of 10

Zoro Select

Zoro Select O-Ring Buna-N Black 3-3/4 in PK10

SKU CH-9PWN-1H79J

Pack of ten Buna-N O-rings with 3.7 in inside diameter and 0.139 in width, rated for -40 to 250 °F and FDA approved

  • Metal-detectable Buna-N seals for food-safe line compliance
  • 10-pack covers multiple maintenance points with one order
  • Medium-hard 50A durometer resists extrusion up to 250 °F
  • Precise 3.7 in ID and .139 in width fit dash-240 grooves
  • FDA-approved material meets sanitary processing standards

Zoro Select Buna-N O-Ring Pack

This pack contains ten black Buna-N O-rings with a nominal inside diameter of 3 3/4 inches. They are made for sealing tasks in fluid and lubricant systems where a medium-hard 50A durometer material is required. The rings are FDA approved and metal detectable for safety compliance.

Build fit and system clearance

Each ring has a nominal width of 1/8 inch and an actual inside diameter of 3.7 inches with an actual width of .139 inches. The nominal outside diameter is 4 inches while the actual outside diameter measures 4.012 inches. These dimensions determine the groove space needed and the sealing surface they will cover.

Thermal range and power draw

The material is rated for a temperature range from -40 degrees to 250 degrees F. This operating window defines the thermal limits the seal can withstand without degrading. The rings are not X-ray detectable, which may affect inspection methods in certain regulated environments.

Highlights

  • Metal-detectable Buna-N seals for food-safe line compliance
  • 10-pack covers multiple maintenance points with one order
  • Medium-hard 50A durometer resists extrusion up to 250 °F
  • Precise 3.7 in ID and .139 in width fit dash-240 grooves
  • FDA-approved material meets sanitary processing standards

Specifications

BrandZORO SELECT

Questions about this item

Will the Buna-N material hold up at the 250 °F upper limit during continuous operation?

The O-ring is rated for a temperature range of -40 °F to 250 °F, so sustained exposure at the top end stays within specification.

Does the 50A durometer hardness mean the rings stay quiet and cool in a pump running all day?

Medium-hard 50A Buna-N resists extrusion and maintains sealing force without generating extra heat or noise in steady service.

What groove dimensions do I need on the mating hardware for these dash-240 rings to seal correctly?

They require a nominal 3 3/4 in inside diameter groove with 1/8 in cross-section width to match the actual 3.7 in ID and 0.139 in width.

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