Jumbo Test Tubes with Stand. Chunky, durable test tubes put serious science safely within reach for young students. Supports inquiry-based investigation and hands-on observation. Plastic tubes are safe at temperatures from 10degrees -200degrees F and feature calibration marks (25, 50, 75 and 100 ml). Hand wash. Includes 6 test tubes, different colored lids (to track experiments), sturdy rack and Activity Guide. Tubes measure 6 inchesH x 1 1/2 inches in diameter. Grades PreK+. LER 2788 Set of 6 plus stand.