The osmotic (the pressure of which water is drawn through a semipermeable membrane) pressure of a substance, i.e. the property that liquids have to equalise concentrations. The patented addition of salt to the LoFric catheter coating is unique. It ensures balanced osmolality and so optimises both water binding and water retaining properties. This considerably reduces the risk of the catheter sticking and causing trauma to the delicate structures of the urethra. The use of catheters without this physiological coating may risk sticking leading to urethral damage.