The reasons of both the strap and the original invoice job because employees have to fill out a computer with 2 points and 1 point when employees fill out the computer must keep the notification job 1 month, then use a strap made from PVC to be brought back in the harness. Because the time to collect the invoice job is not long time employee and point 2 fill a computer completed invoice must keep good time, 2-3 years which is a long time too, so use a piece of paper, any of the factory in order to reduce costs to rise.