This system ensures an even mist spray with even the thickest mediums. The pot is pressurized with high-pressure air up to 80psi and this pressure forces the material up and out through the nozzle. Most underseal sprayers rely on blowing air across the top to suck up the material or use low pressure to spray the material and this makes them likely to clog on thicker mediums. With this gun, the underseal is forced out at high pressure making it very unlikely to clog up. The pressure pot system also ensures a more even and consistent spray. Because you do not normally need to thin the underseal to spray, less drips off and you get better coverage with less waste. The pressurized system also means that extension probes can be used without a loss in performance.