Fire Extinguishers – Part of Your Portland Fire Safety Plan So, what extinguisher do you need? A 3-A:40-B:C? A 1-A: 10-B:C? How about a 2-A: 10-B:C? Well, it depends on the type of fire you have. Let's decode those numbers and letters. in Public bookmarkswith fire_extinguishers Note: So, what extinguisher do you need? A 3-A:40-B:C? A 1-A: 10-B:C? How about a 2-A: 10-B:C? Well, it depends on the type of fire you have. Let's decode those numbers and letters.