The Trumpet of Gabriel was able to send a signal throughout the vastness of space in order to summon Air-Walker’s master, Galactus
Fantastic Four #120 (1971)
Fantastic Four #120 (first time Gabriel used trumpet to call Galactus, 1971)
When Air-Walker first came to Earth he was mistaken for an angel because of his real name and because he possessed the Trumpet of Gabriel. After he announced that all of mankind was doomed, Gabriel used the instrument to summon his master, Galactus, to the planet.