Higher-alarms for larger fires and more serious incidents are assigned as 2nd, 3rd, 4th, and 5th Alarm Assignments as upgrades of a "Still & Box", a "Box", or a "Working Fire". Each alarm level is signified by the level of alarms, followed by the number 11. The number "11" after the level of alarm is tradition of the bell and register system striking 11 blows onto the bell in the firehouse after whatever level of alarm the incident has been upgraded to, followed by the box number, carried over into the modern era.