Calibre 50 is a regional Mexican band. Formed in Mazatlán, Sinaloa, in 2010 by Edén Muñoz, the band has had several lineup changes, with the current roster consisting of lead vocalist Beto Gastélum, backing vocalist & twelve-string guitarist Tony Elizondo, diatonic accordionist Martín "Trompudo" López, sousaphonist Alejandro Gaxiola, and drummer Erick García.
The band is one of the most streamed regional Mexican acts in recent history. Their musical style employs a fusion of norteño and banda music, known as norteño-banda, with low notes played by a sousaphone instead of a bass guitar as is traditional in norteño music.
From Wikipedia (https://en.wikipedia.org/wiki/Calibre_50) under Creative Commons Attribution CC-BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/legalcode)