Has anyone got any idea how these Devil's scrotums work?

In theory you scan the item and place it on the scales.

The scales reject the item. You try again. The ******* thing then allows 4
items through before rejecting the 5th item and freezes up. And never try to
buy dowel using one unless you want large dowel and intend to shove it up
the managers arse when the machine goes wrong.

Not a bad setup.

No tills open and 3 staff watching the 4 self checkout machines. Make that
two staff available when one of them went to find someone that could allow
me to buy my items.

All I need is the correct weight of a nice drill that exactly matches a
large bag of nails, swap the barcode over and I will be even with the
*******s.

Adam