Round luminaire housing in aluminium; for trimless installation in plasterboard ceilings; special edge design with grooves for better adhesion of filler; for ceiling thickness of 10-25mm; surface white powder coated; up to ø450mm: luminaire housing for ceiling installation available in advance; light inset consisting of converter unit and circuit board unit; mechanical connection without tools using twist closure; electrical connection by means of reverse polarity protected plug system; highly reflective coating for improved efficiency; completely homogeneously illuminated, satinised or microprismatic PMMA cover; workplace light suitable for VDUs according to DIN EN 12464-1 (UGR < 19); cover removable without tools for easy maintenance; same luminance for all flat luminaires; energy-efficient LEDs with very good colour rendering; binning initial ≤ 3 MacAdam; available in the light colours 3000K and 4000K; CRI ≥ 80; min. 90 % of the luminous flux after 50000 hours; luminaire with 2 cable openings and plug-in terminals for through wiring; degree of protection IP 20; PC I; photobiological safety according to IEC 62471 risk group 0; DALI dimmable with CLO function; optional non-dimmable; optional with LED emergency light with 1 h or 3 h battery and self test