When sourcing RF modules, you must prioritize Frequency Bands (e.g., 433MHz, 868MHz, 2.4GHz) to ensure they align with your local radio regulations. Key performance metrics include Transmission Range (LOS - Line of Sight), Data Rate (Kbps/Mbps), and Power Consumption, especially for battery-operated IoT devices. Ensure the module supports the required Modulation Type (FSK, GFSK, LoRa, or OOK) and has a high Receiver Sensitivity (measured in dBm) to maintain stable connections in noisy environments.