ViewSonic EP5542, 55" Free-standing Digital ePoster, 3840x2160 Resolution, 400 cd/m2 Brightness, 16/7 operation rating, USB Media Playback, Optional Cloud-based CMS, USB 2.0 x 3, HDMI 2.0 x 3, DP x 1, VGA x 1, Black
HPL210L 380-780 nm LED Brightness Light meter Luminance Meter for cd/m2 nit - AliExpress