The construction of the damper case has enabled
  the Tri-Pro to be successfuly fire, cycle and leakage
  tested to current stringent specifications.

  The design of the Tri-Pro damper case has been
  researched to assist the installer with quick and
  efficient connection to the ductwork, without
  causing interference to the operation of the
  damper, as cost is the essence of all installations.

  The Tri-Pro damper is available in sizes that conform
  to the recent "Rationalisation Initiative" as detailed
  in BS EN 1506: 1998, which is endorsed by the
  Latham and Egan 2001 directive.