LABORATORY APPARATUS, NAMELY LABORATORY WATER BATHS AND WATER BATH ACCESSORIES IN THE NATURE OF WATER LEVEL REGULATORS, LABORATORY SAMPLE RACKS, LABORATORY SAMPLE TRAYS, TEST TUBE AND FLASK CLIPS, GASSING HOODS, GAS FLOW REGULATORS, CONCENTRIC RING SETS AND COVERS AND PARTS THEREFOR; BIOLOGICAL INCUBATORS, CONSTANT TEMPERATURE LABORATORY INCUBATORS, AND PARTS THEREFOR; DRYING AND STERILIZING OVENS, CONSTANT TEMPERATURE LABORATORY OVENS, AND PARTS THEREFOR; CONSTANT TEMPERATURE LABORATORY REFRIGERATORS; CONSTANT TEMPERATURE LABORATORY HOT PLATES; THERMOSTATS; INTEGRATED CIRCUITS; THICK FILM NETWORKS; HYBRID CIRCUITS; RESISTOR NETWORKS; VOLTAGE REGULATORS AND REFERENCES; TIMERS; DUAL IN-LINE NETWORKS; SINGLE IN-LINE NETWORKS; CIRCUIT FLAT PACKS; ENVIRONMENTAL TEST CHAMBERS USED TO TEST ELECTRONIC COMPONENTS AT VARIOUS TEMPERATURES; ELECTRONIC AND GAS CONTROLLERS FOR CONTROLLED ENVIRONMENTAL APPARATUS; MACHINES FOR TESTING THE STRENGTH OR STRETCH OF MATERIAL; AND SUPPORTS USED FOR TEMPORARY SUPPORT OF FLASKS AND SIMILAR EQUIPMENT IN A SCIENTIFIC LABORATORY