Nunc Tissue Culture Flasks feature the Nunclon D surface which provides excellent cell attachment and growth. Nunc offers a choice of cap styles on larger flasks. 80cm 2 and 175cm 2 flasks are available with filter caps, polyethylene plug seal screw-caps and phenolic caps. The polyethylene caps for the 80cm 2 and 175cm 2 flasks have two modes of closure. In the vent position air exchanges takes place through a labyrinth which minimizes risk of contamination. In closed position the plug-seal prevents any air or liquid from escaping. The hard, black, phenolic cap is preferred in some situations because it quickly spins off. The angled neck designs available on 25cm 2 and 80cm 2 flasks provide easy access to the cell monolayer for cell harvesting. Large necks allow easy filling and access with pipets. All Nunc Flasks have interlocking rims to allow secure stacking.