3 A 30V MF-R300 MULTIFUSE 11.4x11.4 mm (Bourns) regenerating fuse to protect equipment. This throughole component that can be placed onboard v3.x right from EC36/25 (+14V supply line).
With the throughole transient protection diode right after it, the supply-spike protection is extended. Useful for non-assembled v3.x, or in the harness eg. 1 for every injector (or for other circuits).