Here are a few different kinds of spanners you might have heard of: 

 

Adjustable wrenches

Open-ended spanners

Ring spanners

Torque wrenches

Flare-nut spanner

Socket wrenches

Spanners are measured in both imperial and metric measures. Example, Japanese cars require metric spanners while most American vehicles need imperial spanners.

 

Most common spanners are used for loosening or tightening hexagonal bolts or nuts with flat surfaces that fit snug into the spanner or wrench jaws. Adjustable wrenches can be used for many different sizes so when applying the maximum tightening or loosening torque isn't required these hand tools are very fast and convenient. They are not recommended however if you need to apply a lot of torque as a fixed jaw spanner can apply more torque.

 

Most good quality spanners and wrenches are drop forged and chrome plated. They are forged from high quality steel such as chromium-vanadium. This is then hardened and tempered to give a hard work face to ensure the tool last a long work life and don't round and burr over the edges.