When sourcing stub ends, you must prioritize material grade (e.g., Stainless Steel 304/316L, Carbon Steel, or Duplex) to ensure chemical compatibility. Pay close attention to the Schedule (Wall Thickness), such as SCH 10S, 40S, or 80S, which must match the connecting pipe. Additionally, verify the Type (Type A, B, or C): Type A is for standard lap joint flanges, Type B is for slip-on flanges, and Type C can be used with either. Ensure the dimensional standards comply with ASME B16.9 or EN 10253 for seamless integration.