When sourcing dive lights, prioritize Lumen output (brightness) and Beam Angle. For technical diving or murky water, a narrow beam (5-10 degrees) is essential for penetration, while photography requires a wide beam (100+ degrees) with a high Color Rendering Index (CRI >90) to restore natural colors. Ensure the Depth Rating exceeds your operational needs (e.g., 100m/330ft for recreational or 200m+ for technical). Additionally, verify the Battery Type (18650 or 21700 Li-ion) and Burn Time, ensuring the light can maintain maximum output for at least 90-120 minutes.