The Normal consists of two racks with the normal bait stoppers. The Combi consists of two racks where part of the stoppers are the normal versions and part of the stoppers are middle extension stoppers. These ensure that the bait is placed on the same hair a little further away from the hook. The Extension stoppers contain two racks with medium and long extension stoppers. This way the bait can be placed even further (on the same length of hair) off the hook. See the three images where the centimeter clearly shows the different distances of the bait from the hook. And that while the hair has the same length. A big advantage of the PB Products Hair Stops is that they can be broken off the rack with all simplicity.