Edelbrock Victor Jr. Nitrous Dual-Stage Plate System #70065 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. The Victor Jr. Dual-Stage System allows you to adjust the first stage to supply 100-150 additional horsepower, then trigger the second stage for 150-250+ hp. Includes all the high quality features of single stage Victor Jr. systems but allow you to add a second stage of nitrous to your engine. This system is for use with 4500 Series carburetors.