Wrenches and Spanners come in a variety of sizes and with different features. For example, Combination Spanners has a closed loop – the box end - on one side and a U-shaped, open end on the other.
The jaw sizes vary by tool, so you might need more than one Wrench or Spanner, depending on whether you work with nuts and bolts of different sizes. A set might be a good value way of solving that problem.
Wrenches are often supplied as an adjustable tool, so can work in different sizes. It’s not unusual for a single wrench to work in up to eight different sizes.
In addition to selecting the right type of tool for your work, think also about the size of the spanner and / or wrench you’re thinking of buying. Is it the right length for you to work with comfortably?