This coaster lights up when a drink is on top. It uses premade LED lights from amazon (http://www.amazon.com/gp/product/B004XEEREY?psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00). The coaster were designed to stack if need be. Still Working on some modifications to make the coaster thinner. You can also cut the spring on the LED to make it more sensitive; uncut it will not light up with a empty beer bottle. #LightItUp I also used glow in the dark PLA so it would glow when drink taken off coaster Leaves comments with feedback if you think I should change something. P.S. Dont judge me...I don't actually drink coors lightThe screw holes are for 8-32 1/4 machine screws. Use some pressure to snap the top onto the middle.