Want to buy NXP pressure sensor. Do not know how to choose, want to get selection help. Pressure sensors are circuit board mounted in three sizes. The first one is differential pressure: 0-2kpa. The second is gauge pressure: -20kpa-5kpa (or absolute pressure: 81,326pa-106,325pa). The third is gauge pressure: 4-6.5 kg. Three are working in negative pressure environment.