Value Collection ZMSCS70903 Silicone O-ring Dash 903 50 Pack

Product Description

The VALUE COLLECTION ZMSCS70903 is a Dash 903 silicone O-ring designed for sealing applications that demand a wide operating temperature range and reliable dry heat resistance. With an inside diameter of 0.301 inches, an outside diameter of 0.429 inches, and a cross-section thickness of 0.064 inches, this round-profile ring seats precisely in standard Dash 903 grooves. Rated from -80 degrees F to 450 degrees F, the silicone compound maintains flexibility and seal integrity across temperature extremes that would degrade many other elastomers. Hardness is rated at 70 Shore A. Each package contains 50 pieces. Licensed HVAC technicians, plumbers, and mechanical contractors install this type of fitting seal in everyday service work.

This O-ring is specified as an O-Ring Boss (ORB) gasket for straight-thread tube fittings, where a face or boss seal is required at the fitting port rather than a tapered thread seal. Typical installations include hydraulic lines, pneumatic fittings, refrigerant-side components, and fluid system plumbing where exposure to oils, chemicals, or solvents is possible. The silicone material also provides good weather and ozone resistance, making it suitable for outdoor or exposed mechanical assemblies. Note that silicone has limited oil resistance compared to nitrile or Viton compounds; verify compatibility with the system fluid before installation.

Key Features

• Dash 903 standard dimensions: 0.301 inches ID, 0.429 inches OD, 0.064 inches thick
• Silicone compound rated from -80 degrees F to 450 degrees F
• Round cross-section profile for standard O-ring groove seating
• 70 Shore A hardness for a firm, reliable seat under compression
• Good weather and ozone resistance; compatible with oils, chemicals, and solvents within rated limits
• Configured as an O-Ring Boss gasket for straight-thread tube fittings

Compatibility

Designed as an OEM-style replacement or service O-ring for straight-thread tube fitting ports requiring a Dash 903 silicone boss seal in plumbing, HVAC, pneumatic, and fluid-system applications.

Installation Notes

This fitting seal is typically installed by licensed plumbers, HVAC technicians, or pipefitters during assembly or service of straight-thread tube fitting connections. Depressurize and drain or recover the system fluid before removing or replacing any O-ring in a pressurized line. Lightly lubricate the O-ring with a compatible fluid or grease before seating to prevent tearing during assembly. Verify that the replacement O-ring material is compatible with the system fluid, especially in oil or refrigerant circuits where silicone has known limitations.