Waterfox provides you with a high-performance 64-Bit version of Mozilla Firefox.
The Firefox source code was taken and compiled to run specifically for 64-Bit Windows computers. It is not a flashy or complex browser by any stretch but it will import all of your Firefox settings and incorporate them making it very familiar to use.
Waterfox is compiled with many optimizations so that it will perform faster and more efficiently than simply redistributing Firefox as a 64-Bit program.
Version History for Waterfox: https://www.waterfoxproject.org/blog/waterfox-55.2.2-release-download