It is a collection of software development tools in one package installation. It is designed to help developing applications for a specific device or operating system (OS). For example, you would like to build a wooden chair and you will require tools such as hammer and nails to put together pieces of woods to be a chair. Similar in developing an application, you will require tools to put it up together. Instead of hammer and nails, the sofrware development kit (SDK) contain necessary software tools for developers to build an application. One of the known SDK is Windows 10 SDK.