Value Collection ZMSCH70443 O-ring Dash 443 Nitrile Nbr

Product Description

The VALUE COLLECTION ZMSCH70443 is a Dash 443 nitrile butadiene rubber (NBR) o-ring designed for static and dynamic sealing applications in plumbing, HVAC, and industrial fluid systems. It measures 7.5 inches inside diameter, 8 inches outside diameter, and 0.25 inches thick with a round cross section. The Buna-N compound delivers strong resistance to petroleum-based fluids and exhibits reliable compression set performance, making it a standard choice for technicians sealing pumps, valves, flanges, and pipe fittings. Hardness is rated at 70 Shore A, placing it in the hard range for positive sealing under pressure. Each package contains 2 o-rings.

This o-ring is suited for residential and commercial applications wherever a Dash 443 NBR seal is specified. Typical install scenarios include pump housings, large-diameter valve bonnets, filter bowls, and flanged connections in systems carrying petroleum-based fluids, hydraulic oil, or water. The wide operating temperature range of -40 degrees F to 250 degrees F supports both low-ambient outdoor installs and moderate-heat mechanical environments. It meets SAE and MIL-Spec standards, making it appropriate for trade and light industrial service work.

Key Features

• Buna-N (NBR) elastomer — the most widely used o-ring material for petroleum product compatibility
• 70 Shore A hardness for firm, positive sealing under compression
• Round cross section, Dash 443 sizing for direct OEM-style replacement
• Operating range of -40 degrees F to 250 degrees F
• Meets SAE and MIL-Spec standards
• Sold in a 2-piece package per order unit

Compatibility

Designed as a direct replacement for any application specifying a Dash 443 NBR o-ring with a 7.5-inch inside diameter, 8-inch outside diameter, and 0.25-inch cross section thickness. Compatible with petroleum products and hydraulic fluids; not recommended for exposure to ozone, direct sunlight during storage, or environments with active electrical ozone-generating equipment. Not FDA approved.

Installation Notes

Installation is typically performed by licensed plumbers, HVAC technicians, or mechanical service professionals. Shut down and depressurize the system completely before removing the old seal and seating the replacement. Lightly lubricate the o-ring with a compatible fluid or o-ring lubricant before installation to prevent tearing during assembly. Do not stretch the o-ring over sharp edges, and avoid storing unused o-rings in direct sunlight or near motors and electrical equipment that generate ozone.