Words with the battery and also with the cord attached while charging. This is so much better than the manual vacuum pump that I had been using. It works quickly to suck the air out of the bag. I like to do a bulk shop and purchase a bunch of veggies and make mire poix for soup and a veggie mix for stir fry and then bag and freeze them for my dinners so I do a ton of prep work on the weekend and then freeze it all for meals during the week in vacuum bags. There's a big difference between veggies that you buy fresh and freeze as opposed to purchasing frozen veggies they are so fresh and don't get mushy and the taste is stronger. This makes short work of the bagging and vacuuming process. I was so happy that I was able to continue using it while it was charging as a lot of items like this don't work when they're plugged in but this does which is fantastic. There are a few bags that come with it which was super helpful and felt like a nice bonus. It's easy to use and pretty much self-explanatory. It's have done any canning with it yet but it is good to reseal your already open jars especially if you have jarred items stored in the fridge that you don't use as much.