Conductive Foil in Pickup cavities and on pickguard

[Colonel Sanders]

My 4003S was shielded completely by the previous owner. He also added Bartolinis. You can take both hands off the bass & no buzz. My Fender has no shielding & buzzed rather badly until I replaced the single coil with a Fralin split coil pickup. My squire has the paint shielding & still uses the stock single coil & has a slight buzz at times. You have to keep contact with the strings to keep the 60cycle to a minimum on these.

The Bartolinis are humbuckers so they are pretty much inherently quiet compared to single coils.