Platooning is one of the most relevant Vehicle-to-Everything (V2X) services which has attracted attention of both academia and industry. High-density platooning has the potential to reduce fuel consumption due to the reduced air drag and to increase the capacity of the roads due to the smoother traffic flow. The aim of this demo is to illustrate the benefits of Vehicle-to-Vehicle (V2V) communication for high-density car platooning. For this purpose, the demo compares Adaptive Cruise Control (ACC), which relies on on-board sensors only, and Cooperative Adaptive Cruise Control (CACC), which relies both on sensor measurements and periodic exchange of Cooperative Awareness Message (CAM) messages among vehicles. During the demo presentation, audience can configure ACC and CACC parameters and observe results of platoon simulation (e.g. average inter-car distance) in real-time. The demo illustrates 5G V2V communication requirements for high-density platooning by showing the impact of CAM message latency and reliability on CACC performance.