It is only the same colour of shot when under the water, and not as visible as black which provide huge contrast. In tests in France for many years it is believed to be the best colour by a long way. The French have been using them years before we knew they existed, always in lead. The tungsten versions are a massive improvement in size and density, in the same colour.

The line is twisted as it acts as a boom and it helps keep the feeder and boom detached from the hook length. They 'kick away' from each other much better like this.