Where a round-cross-section O-ring isn't the right geometry — under a bolt head, banjo fitting or threaded plug — a flat washer does the sealing job instead. FITCO washers follow their own dedicated W-series size range.
A sealing washer is a flat ring, defined by inside diameter (ID), width (W) and thickness (H), rather than a round cross-section. FITCO washers follow their own dedicated W-series size range (W0005–W0475), with an ID progression matched to AS568 O-Rings, so a washer can be sized directly from an existing O-Ring drawing.
| NBR | General-purpose static seal washers for mineral oil, fuel and hydraulic fluid contact |
|---|---|
| FKM (Viton-type) | Higher temperature and chemical-resistant static seal washers for oil & gas and process fluids |
| EPDM | Water, steam and weather-resistant washers — not for mineral oil contact |
Washer width (W) and thickness (H) are set by the cross-section band of the washer's own W-series — use the configurator below to confirm dimensions for your size.
Washer width and thickness are set by the cross-section band, not the individual dash number — confirm your exact gland drawing before finalizing.
Flat sealing washers are used in static seal glands — under bolt heads, banjo fittings and threaded plugs — where a round-cross-section O-ring isn't the right geometry for the joint.
FITCO washers follow their own dedicated W-series size range (W0005–W0475) with an ID progression matched to AS568 O-Rings, so you can size a washer directly from your existing O-Ring drawing.
Send us the dash number or drawing — we'll confirm the equivalent washer size and material.
