Iron Filings Pad (4 PACK / SET) _ Special Purchase Rectangular plastic cased iron filings to show the effect of magnetic force when in the proximity of a magnet. Place a magnet (not supplied) on the pad and the iron filings orientate themselves to show the direction of magnetic force. Size: 3 3/4" x 2 3/4" x 2/5" (97x70x10mm). The hard plastic case scuffs easily, hence the fantastic price we have managed to get these for. Pack of 4 = Excellent Value!