All tracks suffer voltage drop due to resistance in the rails. The further from where the power attaches to the track, the weaker the cars run. With Carrera, the effect is noticeable within 12 running feet of track, the more powerful the motor, greater the effect. Eliminate the low power zones on your track by adding these "jumpers". Use several for very long tracks. The special clips snap easily in the rail under Carrera track. put one end near your existing power inlet and the other in a weak zone. Make long tracks perform MUCH better! Each package boosts power for 2 lanes at points up to 16.5 feet apart. Flat wire design allows running under track, or route under your table. It is compatible with Carrera"s Digital 124, Exclusiv, Evolution and Digital 132 sets.