The Swiss manufacturing company of the TROX group at Rüti, built on the former Swiss HESCO business, holding three live VKF recognitions in Untergruppe 504 Brandschutzklappen — 19316, 23742 and 30932, spanning three separate approval generations, which is the mark of a damper range kept current rather than certified once. Listed alongside the group’s TROX UK and TROX Nederland entries, each of which holds its own national evidence.