These foam pieces are for a Jazz bass pickup, they can also be used for P90s by being mounted on either side of the pole screws. They are placed under the pickup to provide the upwards force to allow the mounting screws to adjust the height of the pickup.
These have springs in the middle to ensure a sufficient, steady and even force is exerted on the pickup. They have adhesive on one side so that they can be stuck securely to the underside of the pickup.
Length: 60mm
Width: 17mm
Height: 14mm