The working principle of a vacuum pump is very simple. It uses a rotating impeller to draw in air from the atmosphere and then expel it. This action creates a partial vacuum that can be used to suck up liquid or gas from another container.
If you have a small retail business, then a handheld POS machine can be a convenient way to take payments without having to invest in a full-fledged POS system. If you run a home-based business, then a handheld POS machine can be an ideal solution for taking payments from customers.