ThinkGeek Star Trek Transporter Pad LED Coasters - Touch-Sensitive Lighting, Optional Sound Effects, 4 Coasters per Set SET OF 4 - Included in the set are four coasters that look like Star Trek: The Original Series (ST: TOS) transporter pads. WITH LIGHTING AND SOUND - The coasters light-up and play materialization or dematerialization sound when someone puts down on or picks up a drink from it. ON, OFF, LIGHT ONLY SWITCH - The lights turn off after 10 seconds. There is also an on, off, and light only switches on the bottom of the coaster to conserve batteries. The coaster needs two CR2032 button cell batteries each (not included). DIMENSIONS - 3 1/2" diameter x 1/2" thick, with each coaster weighing 3 ounces each. OFFICIALLY-LICENSED STAR TREK MERCHANDISE - The Star Trek Coasters are officially-licensed Star Trek: The Original Series merchandise, and a ThinkGeek creation and exclusive.