When purchasing SKD (Semi-Knocked Down) LED kits, you must prioritize the LED Chip (Light Source), the Driver (Power Supply), and the Heat Sink (Thermal Management). Ensure the chips are from reputable brands like Bridgelux, Lumileds, or Osram for high luminous efficacy (at least 100-130 lm/W). The driver should have a high power factor (PF > 0.9) and provide protection against over-voltage and short circuits. For the housing, die-cast aluminum is preferred over plastic to ensure superior heat dissipation and a longer lifespan of over 50,000 hours.