(2x) Standard sized screws used to install your humbuckers from the surrounds and accompanying screws. Humbucker baseplates accommodate two different sizes of screws depending upon where they've come from. Import style baseplates usually are a wider screw hole than USA ones. Here are some dimensions of each:
Import:
Length (excluding head): 26mm
Thread width: 3mm
Head width: 5mm
USA (fits Seymour Duncan, Dimarzio, EMG):
Length (excluding head): 2.5mm
Thread width: 3-48
Head width: 5mm