Push-in connection terminal blocks were developed for direct wire conductor connection. This means that either solid wires or conductors with ferrules can be inserted directly into the terminal block without tools. A special contact spring is opened automatically when the conductor is pushed in, which provides the required pressure force against the current bar. Stranded wire can be connected by simply depressing the orange pusher first, then inserting the wire. The special spring is opened by a push button to release the conductor. The button can be operated with any standard screwdriver (or even a ball point pen). Contact force for the Push-in connection is applied by a special leg spring of high-strength, chromium-nickel spring steel.