The cross directs the flow and removes the swirl from swirl diffusers.
Without a cross the measured value could be too high.
The textile cross is fasten inside the SwemaFlow 4001 650×650 hood with a velcro-type fastening. From May 2016 the 650×650 hood is delivered with Velcro. (Velcro-type fastening can be retrofitted in an older SwemaFlow 4000 650×650 hood – use part no. 769720 when ordering.)
