bcTools-v1.3-d-20.zip is a release file of the Minecraft mod Buildcraft-Tools, made for Minecraft 1.5.2. It was published on July 23, 2013 and is 0.7 MB in size. For the full description, screenshots and every other version, visit the Buildcraft-Tools mod page.
How to install: Put the .jar into the mods folder (.minecraft/mods) and start Minecraft with the matching mod loader profile.