Edelbrock Performer RPM Dual-Stage Nitrous System #70004 is designed for those who want to add power in stages to soften the "hit" of the nitrous system. This is one of the best ways to control excessive tire spin or violent chassis reaction. Performer RPM Dual-Stage System allows you to adjust the first stage to supply 75-150 additional horsepower, then trigger the second stage for 150-250+ horsepower. Include all the high quality features of single stage Performer RPM systems with the additional solenoids and spray bar plate to add a second stage of nitrous to your engine. Edelbrock nitrous spray bars are precision machined on an EDM machine instead of standard drilling, giving you the best flow characteristics available. This system is for use with 4500 Series carburetors and has a silver powder coated bottle.