rubyinstaller-devkit-2.6.5-1-x64.7z

If you don’t know what version to install and you’re getting started with Ruby, we recommend you use Ruby+Devkit 2.6.X (x64) installer. It provides the biggest number of compatible gems and installs MSYS2-Devkit alongside Ruby, so that gems with C-extensions can be compiled immediately. The 32 bit (x86) version is recommended only if custom 32 bit native DLLs or COM objects have to be used.