Quad-Lock Unit Converter (Fedora/Ubuntu) is a freeware tool that can take care of all your unit conversions even when offline. It has an easy-to-use interface and contains more than 900 units commonly encountered while solving engineering or everyday conversion problems. Other features include a function to Find Units and ability to store user-defined conversions. Everything is built into a single file so no uninstaller is necessary. Its small file size makes it easy to distribute among friends and co-workers.