INDUSTRIAL / RESEARCH GRADE QUALITY || Clamps feature solid Zinc die cast construction. High grade, nontoxic. powder coating. Non-ferrous, rust free & long lasting use for any laboratory application 3 FINGER, VINYL COATED || Clamp accepts apparatus measuring up to 8.5 cm (3.4"). Thread fitted actuating joints. Vinyl coated fingers provide a strong, slip-free hold STAINLESS STEEL CONNECTING ROD || Clamp is attached to a stainless steel connecting rod measuring 5.5" in length and 10mm diameter GREAT FOR PROFESSIONAL LABORATORIES, CLASSROOMS & HOUSEHOLD || Designed for use in professional laboratories, but is an ideal choice for science classrooms and household use Ideal uses for beakers, Erlenmeyer flasks, test-tubes, boiling (Florence) flasks, burettes. For securing the clamp to a frame or other apparatus an additional holder (sold separately) will be needed. Please see recommended Boss Head list. The screw adjustment allows for precise pressure when gripping glass objects, to avoid potential breakage. The round extension arm allows the clamp to be rotated 360 degrees as well as vary the distance from the support apparatus. The fingers are coated in vinyl for higher temperature applications.