Sumatra PDF

Sumatra PDF is a free and open-source document viewer that supports a variety of formats, including PDF, ePub, MOBI, CHM, XPS, DjVu, CBZ, and CBR. Known for its simplicity and lightweight nature, it is a popular choice for users who need a no-fuss, quick PDF reader. The application is designed to be resource-efficient, making it ideal for use on older hardware or systems where performance optimization is crucial.