The 450C is a 150 PSI continuous duty cycle compressor that puts out 1.80 CFM at 0 PSI. Although this compressor fills a little slower than the 400C, it is able to run for longer periods of time without overheating. If you're planning on building a show car and will be using you air ride throughout the day of the show, the 450C will be the compressor you want to go with.
