Wires, leads and cables form the basis of most electrical circuitry and in most instances they are most definitely permanent fixtures. When it comes to test and measuring instruments, however, it suddenly becomes necessary for connections to able to be made and unmade in a matter of moments. In the scientific community there is considerable standardisation and the so-called laboratory connectors usually take the form of 4mm banana plugs and the corresponding sockets. Many different plugs and leads are available in a range of standard colours. Many are of the stackable type, allowing for multiple connections. Standard 4mm sockets are the obvious choice for any instrument designed for plug-in leads and these little sockets are more easily fitted by using the special fixing tools. The internal terminals for these sockets are of various types with a simple blade type being popular, but plain pins, solder pins or threaded binding post types can be found. Inevitably, other forms of connection will also be encountered and for these, special leads may be required or in many cases, suitable adapters can be used such as a 2mm to 4mm plug adapter or BNC to double binding posts. Whatever type of connection terminals are found, a suitable lead or adapter is sure to be available.