Fowler 6" 4R Magnetic Steel Rule 52-414-006-0 Fowler's Magnetic Rules are supplied with two of more button magnets to allow convenient storage and use in special applications.Features: 6" range 4R reading Rigid style 4R graduations: 8ths, 16ths, 32nds and 64ths In/mm graduations: 32nds, 64ths, 1mm, 0.5mm