There are 4 sizes. High quality Epistar SMD4014 LEDs gives very high lumen output,up to 120 lm/W. No-UGR version is standard vesrion and UGR<19 version optional. Lifud driver, Philips drivers,OSRAM or Tridonic drivers are also available. Four kinds of installation: Recessed in T-bar ceiling, recessed with clips in plasterboard ceiling,surface-mounted with mounting frame, suspension optional. Extruded aluminum trim, PS LGP and PS diffuser. IP20 as standard, IP65 optional.