Abstract: A seal arrangement for a fluid device includes a seal member that is disposed in a first groove formed in a body and one or more backup members disposed in a second groove formed in the body, with a shoulder between the first and second grooves against which the seal member is supported. The fluid device may be any device that contains a fluid, such as, for example, a valve, a regulator or a fluid connector. The body may be, for example, a stem-like member or other device that is disposed in a bore and for which a fluid-tight seal is needed to prevent fluid flow along the annulus between the stem and the bore wall. The shoulder may be used, for example, to provide a rigid support for the seal member under pressure, in one embodiment supporting about half of the bulk material of the seal member under pressure.