Patent ID: 7476314

Claim:
A keying system for a filtration unit, the keying system comprising: a filter having a filter longitudinal axis and a cooperating holder, the filter and cooperating holder being removably connected and sealed to each other, for conveyance of fluid into the out of the filter from the holder, by two tubular connectors each comprising a male tube and a female tube; wherein at least one of said tubular connectors comprises a key system comprising a tab protruding from an outer surface of the male tube of said at least one tubular connector and a slot provided in an inner surface of the female tube of said at least one tubular connector; wherein said two tubular connectors are adjacent to each other and not coaxial, so that the filter, when connected to the cooperating holder, cannot rotate relative to the cooperating holder on said filter longitudinal axis; and wherein said tab and said slot are mated and in contact with each other when the filter is installed in the cooperating holder and when the filter is in use and fluid is being conveyed into and out of the filter.