This polypropylene rack holds up to 25 thermometers in a safe vertical position to avoid separation of liquid and damage while drying. Hole diameters in the top and middle plates are 7.9mm (5/16") while the bottom plate has placement wells with 3.2mm (1/8") diameter drain holes. The distance between the top and bottom plates is 10.5cm (4 1/8") so thermometers from 6" and up can be accommodated. Steam autoclavable at 121°C.