Triplett 9055 Autoranging Digital Multimeter, 53 Ranges, 40,000 Lux
Amazon.com : ANNMETER Light Illuminance Meter, Digital Luxmeter AN-8801C Measures 0-40,000Lux/ Footcandle with Separate Lumen Sensor, Lux/FC Lights Tester for Plant LED Office : Electronics
DIY Super Bright 40000 Lux LED Light | MrWire - YouTube