Learning Resources Chunky Durable Jumbo Test Tube with Activity Guide put serious science safely into the hands of your youngest students. Features sturdy rack different colored lids and calibration marks at 25 50 75 and 100 millimeters. This tube supports inquiry-based investigation hands-on observation and placed in rack with multiple color lids. Plastic tube is safe at temperatures from 10 to 200 degrees Fahrenheit and measures 6 L x 1-1/2 D inches. Ages 4 and up. Pack of 6 tubes.