The present invention may be directed to an improved LED downlight with enhanced features including a multi-adjustable junction box and cover assembly, and arm and hinge mechanisms for better installation and packaging of said improved LED downlight. The versatile configuration of the junction box, mounting plate arm, and hinge mechanisms may allow the entire assembly to be maneuvered over various sized ceiling holes for ease of driver and LED replacement and maintenance. Other features and improvements may include compact compressible and expandable three-piece hangar bar mounting brackets, an integral air-tight box, and/or a system for mounting the improved LED downlight to various ceiling thicknesses. The improved LED downlight may be used in both new construction and remodel retrofit installations, sharing the majority of parts, providing ease and flexibility for the installer.