Well for starters the item arrived late. But I know that is not the sellers fault. the base is set up for 16, so if you got the 10 pack, there will be some empty. The instructions are VERY unclear so I will have to work to figure that out.The base DOES need to be plugged in order to call the buzzers however it says the buzzers hold charge, so I am not sure what good that does anyone??? There are little red lights that flash, it vibrates, AND it rings for the customer- there is a button on the side where they can turn it off.Other than those few minor details these are perfect for my food truck and will help me avoid yelling people's names / letting their food sit and get cold.