One of the biggest warehouse assistant duties is to scan inventory when it is coming or going. This is typically done with a little handheld scanner.
I remember working at one warehouse where the scanner would chime after each item was scanned, kind of like at the grocery store. The thing was that the chime was really loud and grating. If you had a big shipment you were liable to go mad with the chime repeating itself over and over all night long.