Cross slot small pan head screws and spring washer combination ...
Head: The head of a slotted head grub screw is flat with a single slot that accommodates a flat-blade screwdriver.
RS PRO Slot Countersunk Head Nickel Plated Brass Machine Screw, M6, 20 — Nguyên Xương
RS PRO Slot Countersunk Head Nickel Plated Brass Machine Screw, M6, 20mm; 482-9467
A Practical Guide to Types Of Screw Heads
Types Of Screw Heads - A screw drive is essentially a series of formed protrusions and chambers on the screw head that enable torque to be applied to it.