The well seal effectively isolates the culture from the external environment while providing fluidic resistance to the system. It is specifically designed to prevent medium overflow into the well when high pressure is generated in the lower channel due to the perfusion of culture medium. By sealing the well, the flow in the lower channel is maintained, ensuring a sterile environment. The seal is optically clear and transparent, making it ideal for microscopy. Additionally, the adhesive can be easily removed during or at the end of the experiment, allowing direct access to the sample for complete retrieval of the insert. These seals are sold in packages of 20 units.