Download from PortableApps.com
Version 2.94 for Windows, Multilingual
8MB download / 26MB installed
Transmission Portable can run from a cloud folder, external drive, or local folder without installing into Windows. It's even better with the PortableApps.com Platform for easy installs and automatic updates.
Transmission is a lean, easy-to-use bittorrent client with support for encryption, a web interface, peer exchange, magnet links, DHT, µTP, UPnP and NAT-PMP port forwarding, webseed support, watch directories, tracker editing, global and per-torrent speed limits, and more.