Excellent heat transfer won't interfere with magnetic stirring,Holes spaced for optimum stirring of all vials,Color-anodized for durability and easy identification,Round reaction blocks are designed to fit directly on 135mm diameter, round top hot plate stirrers. Aluminum construction offers excellent heat transfer without interfering with magnetic stirring. All blocks are anodized for increased strength, durability and chemical resistance. A thermowell is provided for insertion of a temperature sensor or contact thermometer. Available for scintillation vials and dram vials.