A clampable conduit comprising a generally rigid layer having a first end and a generally flexible tube generally coaxial with the rigid layer. The flexible tube extends axially in a first direction beyond the first end. The conduit also has a generally rigid sleeve moveable between a cover position,...http://www.google.com/patents/US6186999?utm_source=gb-gplus-sharePatent US6186999 - Rigid clampable cannula
