Check the listing for details. Two Seismic Accelerators Astro Blaster Rocket Balls Kinetic Conservation Energy. Condition: New. Listed at 32.95 USD. Pay only one price flat rate shipping. After the first item there is no additional shipping. You are buying two seismic accelerators. Drop the Seismic Accelerator straight down on the floor and watch as the smallest red ball at the top of the post rockets up to 5x higher than the height of the original drop! Use this ingenious demonstration to help students learn about potential and kinetic energy and conservation of energy. Accelerator comes with 3 small red balls (diameter about 2 cm); a post containing 1 mottled yellow/brown ball (diameter about 2.5 cm), 1 mottled green/yellow ball (diameter about 3.5 cm), and 1 mottled blue/light blue ball (diameter about 4.5 cm); 1 pair of safety glasses; and a teacher's guide. To maintain stability, only the 3 small red balls are removable from the accelerator post. This item is also sometimes called an Astro Blaster.