This is a 2u heat sink

https://www.ebay.com/itm/AMD-epyc-2U-active-SP3-TR4-4-heat-pipe-CPU-radiator-399-H11DSi-/175451260457?nordt=true

This is a 4u radiator

https://www.ebay.com/itm/amd-epyc-server-cooler-4u-sp3-AMD-Threadripper-tr4-/175360235022?nordt=true