Value Collection ZMSCH90249 O-ring Dash 249 Nbr 90 Duro

Product Description

The VALUE COLLECTION ZMSCH90249 is a Dash 249 Buna-N (Nitrile Butadiene Rubber) O-ring engineered for sealing applications in systems that handle petroleum-based fluids and hydraulic media. It measures 4.875 inches inside diameter and 5.125 inches outside diameter with a 0.125-inch cross-section thickness. The compound is rated at 90 durometer, placing it in the extra-hard hardness range for applications requiring high compression resistance and dimensional stability under load. Licensed plumbers, hydraulic technicians, and HVAC service pros install this ring wherever a robust, petroleum-resistant static or dynamic seal is needed.

This O-ring suits residential and commercial plumbing, hydraulic systems, pneumatic assemblies, and industrial fluid-handling equipment where petroleum product compatibility is required. The Buna-N compound provides excellent resistance to oils, fuels, and petroleum-based lubricants. It is not recommended for applications involving ozone exposure or direct UV storage, so installation in enclosed housings is preferred. The Dash 249 sizing is a standard AS568 dimension used across a wide range of OEM and aftermarket equipment.

Key Features

• Buna-N (Nitrile Butadiene Rubber) compound — the most widely used O-ring elastomer for petroleum-fluid environments
• 90 durometer extra-hard rating for high compression resistance and reduced extrusion under pressure
• Operating temperature range of -40 to 250 degrees F for broad service applicability
• Excellent compression set, tear resistance, and abrasion resistance for long service life
• Meets SAE and MIL-Spec standards
• Round cross-section profile; black color

Compatibility

Compatible with petroleum products including oils, fuels, and petroleum-based lubricants. Not suitable for use with ozone-generating environments or direct sunlight exposure. Conforms to SAE and MIL-Spec standards for Dash 249 O-ring dimensions.

Installation Notes

Installation should be performed by a qualified plumber, hydraulic technician, or mechanical service professional. Shut off and depressurize the system fully before removing the old seal and installing the replacement ring. Lubricate the O-ring with a compatible petroleum-based or system-appropriate lubricant prior to seating to prevent tearing during installation. Do not store or install near motors, electrical equipment, or other ozone-generating sources, as ozone degrades Buna-N compound.