When sourcing pressure gauges, you must prioritize accuracy classes (e.g., Grade A or Grade 1.0/1.6) to ensure precise readings. The dial size (typically 2.5", 4", or 6") should match the visibility requirements of the installation site. Crucially, verify the wetted parts material; for corrosive environments, 316 Stainless Steel is mandatory, whereas Brass is sufficient for non-corrosive air or water applications. Additionally, consider liquid filling (Glycerin or Silicone) to dampen vibrations and pulsations, which significantly extends the gauge's lifespan.