GHS Boomer 7 String Heavy Electric Guitar Set (13-74) Boomer 7 String Heavy Electric Guitar Set (13-74) Modern guitarists are tuning lower and lower, adding more strings for a broader tonal spectrum Designed with the help of many "extended range" guitarists, these 7-String Boomers sets bring what you love about GHS 6 string sets into lower, uncharted territory! Gauges: 13-17-30-42-54-64-74 Modern guitarists are tuning lower and lower, adding more strings for a broader tonal spectrum Designed with the help of many "extended range" guitarists, these 7-String Boomers sets bring what you love about GHS 6 string sets into lower, uncharted territory!Gauges: 13-17-30-42-54-64-74