Single polished 2.5 lb bottle ,single nozzle system for two cylinder engine with a single carb. Complete with "Lightning" nitrous and fuel solenoids, braided stainless hoses, "Piranha" nozzle, fuel pump, relay, microswitch, arming switch, jetting for 15, 25, 35, and 50HP Polished 2.5 lb bottle. Billet aluminum bottle brackets.