SDK Tools is a downloadable component for the Android SDK. It includes the complete set of development and debugging tools for the Android SDK.
If you are new to the Android SDK, the SDK starter package installs the latest revision of the SDK Tools in the directory.
If you are already using the SDK and you want to update to the latest version
The sections below provide notes about successive releases of the SDK Tools, as denoted by revision number. To determine what revision of the SDK Tools you are using, refer to the "Installed Packages" listing in the Android SDK Manager.