Mine has Santech 64536922944 cores. It's a two seal type. One seal is where it touches the port. The other seals the bottom where refrigerant enters. Rub A/C oil on the seal when replacing them. I think the OEM seals are dual seal types. Single type seals are 90's and older types. More like, they do have two seals. The second seal is inside the core. Newer styles have a visible seal mostly at the lower core portion. Cores are much larger too.

__________________
'06 X5 3.0i - bought @143,123 miles (12/26/20)