This is a blue aluminum tag, “AEC 103A”, (40x100mm) used on the Dinoplex units on the Daytona coupes. It warns against loosening the battery cables when the engine is running. Blue AEC 103 A Dinoplex tag for Dayonas
The later 275 and 330 desings reverted to the crescent-shaped aluminum tags as had been used on the earlier inside-plug 250 cars. The filter element number that is stamped in the “Tipo” block on the tags has changed from “AT4094” on the inside plug 250s to “2228.01” for the 275/330s. 275/330 crescent-shaped air cleaner tag.
From the early 1950s until about the time of the introduction of the outside plug 250 engines in 1959, Ferrari used the black Magneti Marelli B-7 design coils. These were slightly larger than the B-5s and again had the mounting bracket spot welded onto the cans. The whole assembly was painted satin finish black and the aluminumB-7 tags were attached to the bracket with two tiny “u-drive screws.” The usual practice was to cut off the ends of the aluminum tags, at a 45-degree angle, near the end of the lightning bolts and then attach them with one rivet on each tab. I have alos seen original pieces with full-length tabs and using two rivets on each tab. Blue aluminum Magneti Marelli B-7 coil tags.