Sizes Ø 80–630 are constructed with a DTU damper with an attached combination motor shelf (KOMHY). The damper lacks a handle and has an extended shaft to eliminate the need for the handle extender (VREDF).
Sizes Ø 80–315 meet pressure class C when closed.
Sizes Ø 400–630 meet pressure class B when closed.
Sizes Ø 800–1000 meet pressure class A when closed.