Nitrous Oxide System - NOS Dual Stage Big Shot Nitrous System (02402NOS)Big Shot Dual Stage Single Carb Nitrous System Note: This system incorporates two sets of nitrous and fuel solenoids so that power can be added in two events. This first stage is activated by a throttle switch while the second stage is activated by pushing a button or optional 741 15838A Precision Delay Timer. Activation of the second stage automatically deactivates the first stage. Type Holley DOMINATOR Flange Bottle With Bottle Usage Strip