When sourcing a flow reactor, the most critical factors are material compatibility, pressure ratings, and thermal control. You must ensure the wetted parts are made of materials like Hastelloy, Borosilicate glass, or PTFE to resist corrosion. For high-pressure synthesis, verify that the reactor can handle at least 20-100 bar depending on your process. Additionally, look for units with integrated heat exchangers that provide a high surface-area-to-volume ratio to manage exothermic reactions safely.