Diameter: 3.40 in Height: 1.70 in Slot Width: 0.18 in Slot Length: 2.50 in Clicking the switch on top of the base will turn on the light, select a color, and then turn off the light. Colors are Red, Green, Blue, Yellow, Cyan, Purple, and White, finally flash automatically through all seven colors! Bright, Efficient LED Light Source -- Eight LEDs are located inside the base to provide safe, cool, bright light. Please be aware that acrylic sheet thickness will vary from supplier-to-supplier and batch-to-batch. Generally, 3/16-inch thick (also known as 4mm thick) acrylic fits well.