The C20S and C30S are available with two different coulometer cells – with or without a diaphragm. For most applications, we recommend the cell without the diaphragm because it is almost maintenance-free. Due to its innovative design, this diaphragm-free cell from METTLER TOLEDO can even be used for the determination of water in oils. The version of the cell with a diaphragm is recommended for applications such as the determination of water in substances containing ketones. It is also recommended if the best possible accuracy is required.