Heat sealing offers a 100% effective method for plate sealing for a complete seal integrity, as well as being quick and cost effective. Our Gas Permeable Heat Seal Mark 2 is made from a woven material and is designed for use in cell culture, due to its porous nature. The small pore size - <20 µm - of this material enables gas exchange, per 24 hours of >20 g/m2, whilst evaporation is reduced to a minimum. The seal is compatible with polypropylene, polystyrene and cyclic olefin copolymer (COC) plates. It can be removed by peeling, or it can be pierced with a pipette tip manually, using a liquid handling robot or with our Pierce Plate (4ti-0398). Gas Permeable Heat Seal Mark 2 can be utilised for effective overnight incubations, during which it demonstrates significant reductions in evaporation compared to lids. It can also be used for insect and seed storage as it enables gas exchange, whilst providing an inert surface with no adhesive to interfere with the well contents.