Husqvarna Hex Flange Lock Nut No. 532-40-91-48. This is an original husqvarna flange nut. This replaces part numbers 73900600, 83923, 409148 and 532409148.
Husqvarna Hex Flange Lock Nut No. 873900700. This is an original husqvarna nut that measures 7/16 - 14. Replaces part number 873 90 07-00 and 873-90-07-00.