When sourcing Silica Alumina Catalysts, you must prioritize the Alumina content (typically 10-25% or 70-80% depending on the application), as it directly influences acidity and catalytic activity. Key physical parameters include Surface Area (BET method), which should ideally range between 200-500 m²/g, and Pore Volume, which affects diffusion rates. Additionally, verify the Particle Size Distribution (PSD) and Crushing Strength to ensure the catalyst can withstand high-pressure industrial environments without attrition.