Spanners, also known as wrenches, are hand-held tools used to turn nuts and bolts. They come in a variety of sizes and types, and each one is designed to fit a specific size or type of fastener.

Here are some common types of spanners:

1. Open-end spanners: These have a U-shaped opening on the end of the tool and are used to turn nuts and bolts that have two flat sides. They come in different sizes to fit different nut and bolt sizes.
2. Combination spanners: These have an open-end on one side and a box-end on the other. The box-end has a closed-in shape that fits over the nut or bolt head and provides more torque than the open-end. Combination spanners are available in both metric and imperial sizes.
3. Adjustable spanners: These have an adjustable jaw that can be opened and closed to fit a variety of nut and bolt sizes. They are also known as crescent wrenches or shifting spanners.
4. Socket spanners: These are used with sockets that are attached to the end of the tool. The sockets come in different sizes and can be changed out to fit different nut and bolt sizes. Socket spanners are available in both metric and imperial sizes.
5. Pipe spanners: These have a curved jaw that is designed to fit around pipes and other cylindrical objects. They are used to turn nuts and bolts that are located in tight spaces.

When selecting a spanner, it’s important to choose the correct size and type for the specific application. Using the wrong size or type of spanner can damage the nut or bolt and make it difficult to remove or tighten. It’s also important to choose a spanner with a comfortable grip that allows for a good grip and control during use.