This is a replacement Teflon sealing washer for a CGA-678 gas regulator inlet fitting. CGA 678 fittings have a gasketed connection that requires a flat washer to make the seal. The washer is typically not resueable, so it's good to keep a few spares on hand.

Dimensions:

• Inside Diameter: 0.295 in.
• Outside Diameter: 0.609 in.
• Thickness: 0.064 in.

CGA-678 sized gas regulator fitting are authorized for use on regulators containing specific gases at specified maximum pressures. Please check the downloads for a list of appropriate gases for which it is authorized.

CGA fittings are standardized and authorized for the attachment of regulators and transfer lines to gas cylinders filled with specific gases at defined maximum pressures. The three digit number, CGA (XXX), corresponds to the specific gases for which that fitting is tailored (see the downloads).

Connections to cylinders should never be forced. CGA fittings mated between regulator and cylinder never use pipe dope or PTFE tape. CGA connections use either a bullet-nose or gasketed seal. The bullet nose connection has a metal-to-metal contact and seal. Some bullet-nose connections have an o-ring to help improve the seal and to allow a connection to be made without a wrench (hand-tight connections). A gasketed connection requires a flat washer to make the seal. CGA fittings are available in several materials including brass, stainless steel, nickel or chrome-plated brass, and Monel. The CGA fitting material to use depends on the gas and cylinder pressure.