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 10 »-200 »F and features calibration marks (25, 50, 75 and 100 ml). Includes 6 test tubes with different colored lids, sturdy rack and Activity Guide. Hand wash. Tubes measure 6"H x 1-1/2" in diameter.