THE RARE EARTH MAGNET...

...is a dangerous wee beastie. This little chap has a diameter of only 2cm but has a pull of about 10 kilos - when two approach each other - better not let any skin get in the way - they have a wicked bite!

On the other hand they are brilliant tool for gluing supports under vicious cracks - it takes a bit of thought to get everything well  aligned - that's the bit I like