Tool kits offer a selection of different hand tools and are usually supplied in a tool box or a tool bag. They can generally be used as a way of making a large set or a specialised set of equipment portable so that they can be used in a variety of different environments.
These sets of tools are normally grouped by a particular purpose or type of tool. For example, you may see an electrician's hand tool kit with a variety of different tools for this specific field. You may also have a tool kit with a range of different screwdrivers to have a broader application in more settings.
The number of tools within a kit can vary greatly, from two or three key pieces into the hundreds. There are also variations where they may contain only the essential pieces, but they may also consist of all the attachments that may be required across a wider range of use, for example a larger set of ratchet spanners and sockets that includes all metric and imperial sizing.
The price of a tool set will vary greatly dependant on brand, how many pieces and what application it would be used for. These are all factors to consider when purchasing a new tool set. A high-quality complete tool kit could be higher in price but gives you the return of long-lasting tools as a better investment.