Extension bars, sometimes called 'extender arms', allow access to nuts that are difficult to reach, typically in automotive applications.
This Teng Tools extension bar has a 3/4in Square Drive. It is manufactured from Chrome Vanadium Steel for strength and durability and has a satin finish.
The TENM340020 extension bar has the following specification:
Drive: 3/4 inch.
Length: 100mm (4 inch).