Yes, the magnets are so strong that even a round brush will stick well, as long as the canister is metal. Tip: Too many coats of paint on the metal canister of the brush or on the Brush Magnet reduces the magnetic force, so keep both surfaces more or less clean.
Length 128 mm. Width 30 mm for the magnets, 22 mm for the flexible strip; Thickness 6 mm for the magnets, 2 mm for the flexible strip