These chunky, durable test tubes put serious science safely within reach for young students! Encourages inquiry-based investigation and hands-on observation and supports serious science experiments — plastic tubes are safe at temperatures from 10°-200°F and feature calibration marks (25, 50, 75 and 100 ml). Includes 6 test tubes (measuring 6" x 1.5" in diameter), different colored lids (to track experiments), sturdy rack and Activity Guide. Hand-wash tubes only. Ages 4 and up.