Testo-0554-4173-Funnel-Set-417-&-Flow-Straightener-Testo-0554-4173-P-The-Testo-0554-4173-is-a-Funnel-Set-&-Flow-Straightener-Funnel-Set-Testovent-417-that-enables-a-correction-of-the-swirl-into-a-parallel-flow-from-air-conditioning-outlets-Testo-is-the-only-manufacturer-to-offer-a-solution-for-swirl-outlets-The-Funnel-Set-Testovent-417-is-designed-for-the-measurement-on-ventilation-grilles-&-disc-outlets-However-if-the-flow-rate-is-measured-at-swirl-outlets-the-swirl-will-influen