2000-2004 legacy, Outback rear axle.
make sure it’s a Subaru OEM axle. they’ll have a green cup like I’m this example picture:
https://www.ebay.com/itm/273843602467?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=273843602467&targetid=1645685073288&device=m&mktype=pla&googleloc=1023819&poi=&campaignid=20133407470&mkgroupid=147476396765&rlsatarget=pla-1645685073288&abcId=9312979&merchantid=108560327&gbraid=0AAAAAD_QDh9LOZz4eXXXBiZuxfnKtt5rn&gclid=EAIaIQobChMIoIaZl_GzgAMVETjUAR0rlARTEAkYASABEgKUWfD_BwE