Silicone Sponge Cord

The cell structure of an open-cell sponge is very different from that of a closed-cell sponge. In a closed cell sponge, every single cell is a fully enclosed sphere that holds air inside of it. Due to the lack of communication between the cells, water, moisture, and dust cannot easily penetrate the cell structure as they do in an open-cell environment.  

Due to its extremely low water absorption, the closed-cell sponge is excellent for sealing applications where it is necessary to keep dust and water out of the system.