A catheter system having an intussuscepting balloon and a handle for a catheter system. The handle includes a fluidic system for preventing overpressure conditions during balloon intussuscepting and includes a locking mechanism disposed outside of the fluidic system for preventing unintended or accidental movements of a plunger assembly included in the fluidic system. The system includes standard sized components and non-standard sized components. During handle assembly, specific sizes of non-standard sized components are selected to match the length and/or the diameter of a specific selected balloon and are assembled with the standard sized components to form the catheter system.