wolvolk friction powered oil tanker truck toy with lights and sounds for kids wolvol the wolvol oil tanker truck toy is ready to run out of the box. pull out the plastic piece from the battery area so the batteries would activate. press the button on the side of the cab so the lights and sounds will perform. an extra plus is the installed friction on the wheels which allows the truck to move ahead on its own once you push it a little. great gift toy for kids who love light up trucks. suitable toy for boys and girls all ages.