Thank you for your enquiry Can you please advise heater manufacturer and model?
The item you have messaged on is designed to clip onto a straight outlet hood of an Eberspacher airtronic heater part 221000010016. It cannot be used to join two lengths of 60mm ducting together
Neither Webasto or Eberspacher supply 90 degree ducting elbows in 60mm … but they both have heater unit outlet adapter hoods to direct the air at 90 degrees immediately as it exits the heater - very handy and elegant solution when the heater install plan is limited for space. For Eberspacher ( Espar ) D2 Airtronic ( also S2 and S3 Airtronic ) please search 221000010020 For Webasto Air Top 2000 ST C please search 29849A
Hope this helps