Brief introduction on photoluminescet metal coating technology In the world, we are the unique manufacturer who can coat photoluminescent(pl) powder on metal surfaces, such as aluminum, steel, stainless steel, copper... With 10 minutes' being irradiated in the sunlight, it can remain luminous at least 12 hours! Class d passed, the highest class in pspa I would like to show you our test method and result. If possible, would you please run the test by your local authorized institution? Light source:3 pcs toshiba fl20t9d119 wattbrghte daylight(insteadof sunlight) Distance from the light source to the pl metal plate:2.3 meter Time of exposure:20 min(ifexposed in sunlight,10 min is enough. ) The letter size on pl metal plate:2" x 1" ** in dark room without any light,20 hours latter. Human eyes can identify the direction of arrowhead and all the letters can be read without any mistake. Please note that human pupils need 1~2 minutes to fit the sudden darkness. In the darkness, a