Tight 90 degree bend for ventilation ducting. One end is 38mm ID and has a groove that fits into a 45mm hole in bulkhead or airbox up to 2mm thick.
Other end is 43mm ID. You can bond 38mm ducting inside with Polyurethane or Silicone sealant or 50mm ducting on the outside.
RUBBER ELBOW #RUBELB