1688-9RA1224P4G001-ND (9RA1224P4G001) is a 24VDC 120 x 120mm fan that has 4 wire leads made by Sanyo Denki America. The series datasheet doesn’t clarify how long the wire leads are, though.
Sanyo Denki Product Page
If you look up the manufacturer part online, you can reach the San ACE product page. A different catalog page shows up here. Page 171 should be relevant:
The length should approximately be 300mm with some tolerance.