The 8SU is the Fender Precision Bass (P Bass) replacement pickup. They are highly respected by musicians and luthiers alike for their vintage voicing more lows and low-mids. They have lower output than 8CBP.
The two pickups in the P-Bass pair overlap each other by 3/4 (19mm).
The original series bass pickups with passive designs. They are cast in epoxy to remove unwanted feedback and microphonics.