3/4"x.125" (1/8") N45 Grade Neodymium magnets are the strongest permanent magnets.  Extremely strong magnets, use caution.  Great addition to any shop.  Glue them to a tool and stick it to your lathe.  Glue them to the wall to hang your tools.  Turn a small knob out of scrap exotics and you have a nice fridge magnet.  See my free instructions here.  Compare to $2 each at PSI. Item # MAG75