With design elements borrowed from the standard Model 648, the Model 648UHV offers the user all the same features with improved vacuum integrity. Terminating in 6" diameter, all metal sealed flanges (as Conflats*), this assembly utilizes only several small O-rings. Adaptable to standard all metal sealed instrumentation or assemblies, this unit is capable of working well into the low 10-8 torr vacuum region. When working with delicate foil or VYNS type filters, this assembly's high conductance design might prevent blow outs caused by differences in vacuum.