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 650x650 hood with a velcro-type fastening. From May 2016 the 650x650 hood is delivered with Velcro. (Velcro-type fastening can be retrofitted in an older SwemaFlow 4000 650x650 hood - use part no. 769720 when ordering.)
Fits 650x650 SwemaFlow 4001/4000 hood with Velcro inside.