Flex-head spanners have heads that swivel in a stirrup, allowing the spanner to be used at different angles, increasing the reach of the spanner.
The stirrup is made from the base of the head or the end of the shaft. A stirrup on the end of the shaft can allow a head to have two profiles.
All spanner head types can have a flex-head design. One of the most common spanner designs is a combination spanner with a fixed open-ended head and a flexible ratcheted ring head (see What is a combination spanner?).
Flex-head spanners with socket heads are also common. Socket heads are similar to box spanners and fit over the top of the fastener head to cover the whole of it during use. Scaffold spanners are an example of flex-head socket spanners (see What is a scaffold spanner?).
