Exploding firework (6)
(Other definitions for banger that I've seen before include "Noisy old car or slang sausage" , "Old car (colloq.)" , "Sausage, firework and old car" , "Slangily, a noisy old car or a sausage" , "It might just drive" .)
(Other definitions for squib that I've seen before include "Firework (disappointing, if damp)" , "Lampoon; firework" , "Small explosive, often damp" , "Firecracker" , "Small hissing firework" .)