Sumatra PDF Portable is the lightweight Sumatra PDF viewer packaged as a portable app, so you can view PDFs on the go.
Sumatra PDF Portable- это легкий, свободный, с открытым исходным кодом PDF Reader для Windows, имеет минималистичный дизайн.

Sumatra PDF Portable is a slim, free, open-source PDF viewer for Windows.
Sumatra PDF Portable has a minimalistic design. Simplicity has a higher priority than a lot of features. It's small and starts up very fast.

Простота имеет более высокий приоритет, большое количеством функций.
Программа маленькая и стартует очень быстро, разработана для портативного применения, ничего не пишет в реестр, вы можете запустить ее с внешнего диска USB.

What's New in version 1.4
* browser plugin for Firefox/Chrome/Opera (Internet Explorer is not supported). It's not installed by default so you have to check the apropriate checkbox in the installer
* IFilter that enables full-text search of PDF files in Windows Desktop Search (i.e. search from Windows Vista/7's Start Menu). Also not installed by default
* scrolling with right mouse button
* you can choose a custom installation directory in the intstaller
* menu items for re-opening current document in Foxit and PDF-XChange (if they're installed)
* we no longer compress the installer executable with mpress. It caused some anti-virus programs to falsely report Sumatra as a virus. The downside is that the binaries on disk are now bigger. Note: we still compress the portable .zip version
* -title cmd-line option was removed
* support for AES-256 encrypted PDF documents
* fixed an integer overflow reported by Jeroen van der Gun and and other small fixes and improvements to PDF handling