Versatile 4" Round aperture recessed LED downlight with a wide range of lumens and optical controls. Two-stage optical system for smooth light distribution and focus control. Quick change LED module with interchangeable optics for job site adjustment and fixture maintenance. Shallow plenum design. Tool-less driver and j-box access. Posi-lock trim retention torsion springs. See RDZO4 series for trimless plaster or wood ceiling.