2×4 light LED panels are a direct drop in for t-bar/suspended ceilings or they can be surface mounted with tabs included. Tabs are also used for securing the lights in the suspended ceiling for Earthquake certification. LED lights are catching on fast here in the US as they offer up to 60% savings over conventional lighting. They are only marginally more efficient than fluorescent lighting, but their lifespan offsets the price point. LEDs are expected to last approximately 50,000 hours. If the unit is to be surface mounted, there needs to be a ½ inch hole behind the unit for the power cable to pass through. The panels can also be suspended with wire using the supplied tabs. Installation and wiring should be done in accordance with local laws and regulations. These vary from area to area. Consumers should check with local officials to insure the installation conforms to applicable laws.