Installation Recessed mounting in ventilated or unventilated suspended ceilings. Two optional designs. VTB - for suspended ceilings with visible T-bars 25 mm. 300x300 also for fixed suspended ceilings. HB - for suspended ceiling with concealed T-bars. Supplement with fixing brackets for fixed suspended ceiling, see accessories. The luminaire must not be covered with insulation. For further details please refer to the assembly instructions on our website Connection nection in ballast box. The ballast box can be detached and positioned next to the luminaire. Snap-in terminal block 3x1,5?mm² (5x1,5?mm² where dimming is required). Through-wiring possible for 600x600. Design Luminaire body in white enamelled sheet steel (RAL 9016). Louvre Delta - microprism louvre in acrylic (PMMA) with a thin opal diffuser (acrylic/PMMA) on the inside (PMMA). Miscellaneous Enclosure class IP 44 under suspended ceilings and IP 20 above suspended ceilings.