The ZX513-HL-CW-9 fixture is Lighting Facts independently tested and certified. The fixtures' sleek design is less than 1 Inch in height and is linkable with connecting cable (included) or can be linked end-to-end (connector tab included) with additional fixtures to have longer continuous light. The ZX515-HL-CW-9 LED fixture has an internal power supply and Hi/Lo switch, also a CRI of 90+ for perfect color rendering. Just plug it in and turn it on! UL & CUL Approved. Lighting Facts approved.