(McCormick Scientific) This sealant uses the heatless method for sealing any type of capillary tube. Vinyl plastic will not dry out. Press tip of tube into CritosealŽ sealant and twist slightly. Values can be read with any hematocrit tube reader. Tip-resistant Identi-tray has 24 numbered slots with two holes each, allowing storage of double tube samples. Each tray contains enough sealant for several hundred tubes. Six trays of sealant per package.