The Klettersteig Rider 3.0 is a dual system via ferrata kit. It has a carabiner like standard via ferrata kits have and a “rider” system. The “rider” system fixes to the via ferrata cable and progresses with you. As you get to a part where you need to switch you move the rider system up first and then you move the carabiner.
What I like about this system is that if you slip or lose grip of the rungs for any reason you will only fall the length of the connector rather than the length from where you are to the most recent pig tail. This reduces the fall distance by a considerable amount.
The Via Ferrata where I would most like such a system is Leukerbad. On the Leukerbad Via Ferrata when you get to the last third there are few handholds so you rely on finger and arm strength to progress and you get tired. With this system you would relieve that strain to some extent. It would make me feel more at ease.
At 229 CHF from at least one online shop this kit is expensive. You can get Via Ferrata sets for between 60-115 CHF as a beginner. This kit is interesting for people who, like me, have practised Via Ferrata for years and use their kits every weekend in summer. Via Ferrata sets can last for years so if you estimate that you will use it from 3-5 years the price is acceptable.
An alternative is the Austrialpin Hydra via