Does anyone know where RFS Units as defined and stored? This screenshot is from an assembly item > RF-SMART > RF-SMART Multiple UPC tab> I don't know if this is an RF-Smart cust value or a NS value. I have searched all over the customization pages with no luck. thanks!

They are netsuite UOM values.

correct those are multi UPC values associated to a Netsuite Unit type

You can modify them here