A useless tool

Some time ago I came across this ridiculous vernier caliper knockoff that was so preposterous I needed to buy it:

As any of you who've used one of these things knows, a true vernier caliper is a precision measuring tool which has perfectly machined grooves which line up just right, to allow measuring fractions of a millimeter to great accuracy, see this Wikipedia page for some details.  But since these measurements depend on precisely machined and assembled stuff, they can be expensive.

Check out the close-up of the measurement reading window:

You'd get far better accuracy using a traditional ruler!  Well, for those interested, this baby is available at the bargain price of $3.95 at Amazon.com.  But for the life of me I can't figure out those positive ratings - this thing is really, truly, a magnificent piece of garbage.