Laptops are a type of personal computer which you can use anywhere. They are also known as a notebook computer, for example the Lenovo Thinkpad. Laptops can weigh as little as 0.6 kilograms. So they are easy to carry around. These computers can run on batteries, but they can also use mains electricity. Laptops are very popular because they are cheaper than before. You can use them anywhere, such as libraries, canteens, on a train, or even in the street. They are useful for work or study, and also for entertainment.