Just what is this "plastigauge" and where can I get one?

>===== Original Message From Chuck Meanley <CMeanley@AOL.COM> =====
>When doing a bottem end rebuild, two things are critical; a machinest you can
>trust who will tell you the undersize and will normally provide the bearings
>for you ( this is not the time to go cheap, buy the good ones, this rules out
>any third world product) and something I haven't seen mentioned which is
>plastigauge to check the machinest work and make sure everything is within
>tolerance.
>Chuck