Where to buy from sound and led 1/2" shank or ER25 edge finder, ?

[magicniner]

The cheap ones are solid and don't have much flexibility at the tip so for me the advantage is that when I've snuck it up on the work edge until the light just comes on and then set the DRO appropriately in Mach3 the ball just moves over on it's spring when some klutz hits the wrong button and tries to plough it through the work, then the ball simply pops back when I correct my error.
Don't put your tongue on the end BTW, there's 2 12v batteries in series inside mine! ;-)

- Nick