When stripping the insulation from wires it is very time consuming, so many connectors meant for rapid assembly now use Insulation Displacement Connectors so that the insulation need not be removed from the wires. They normally take the form of a fork-shaped opening in the terminal, into which the insulated wires are pressed then automatically cut using sharp contacts, the insulation is severed and the contact is then made with the conductor. To make these connections reliably on a production line, special tooling is used, this then controls the force applied during assembly. If correctly assembled, these connections are gas tight and will last the duration of the products life. A good example of this is a flat ribbon cable which uses up to 40 wires, to terminate each wire individually would be time consuming and prone to errors, but an insulating displacement connector can terminate all the wires in one stroke. These terminals are mainly used for signal purposes and low voltages as in telephone wiring, wires carrying more than a few amperes are better suited to a more reliable means such as press-on connectors as found in the car industry.