For use with 18mm screw necks, 13-18mm Culture Tubes, 18-25mm Culture Tubes, 38mm Culture Tubes, 25-50ml Erlenmeyer Flasks, 125-300ml Erlenmeyer Flasks, 500-1000ml Erlenmeyer Flasks, 25-125ml DeLong Flasks and 250-6000ml DeLong Flasks. Sealed-in Silic