This most useful of tools comes in an array of shapes and sizes, from the large square with four magnets attached down to the smaller circular dish-sized versions, perfect for plunking down onto a steel motorcycle frame while changing a battery or lining up tiny carburetor screws. The primary task of the magnetic tray is obvious, as a portable place to put nuts, bolts, washers, or anything else safely away from falling into the black hole of the engine compartment or, less metaphorically, down the intake manifold and into the number one cylinder.