The GFB Whistling Trumpet 5702 is designed to offer a different sound from the standard trumpet and is an alternative for customers who want a unique, piercing whistle. It is specifically aimed at low boost applications where the 5701 trumpet may not work as effectively. The 5702 trumpet emits a whistling sound more easily and at a slightly higher pitch compared to the 5701, and is compatible with all GFB valves, except for the T9003 and T9503 models.

This trumpet works best when the valve is configured to vent most or all of the air through it, as the velocity of the airflow is what produces the whistle. The 5702 is ideal for use with Respons and Deceptor Pro II valves, where higher boost or RPM is not a requirement to achieve the desired whistle sound.