I worked as an inventory counter for a few months before getting hired as a full time receiving assocaite. We counted the inventory the hard way...no hand held machines for us, so in that job you had to have three things
1. Be able to count--you would not beleive how many people think 1 plus 1 equals 4
2. Be able to do repetitive task--count is repectitive.
3. A keen eye