Gwenith, Sorry I was so vague, I'm a bit embarrassed by my ignorance in this subject! :stone It's the Intraventricular ICP Monitor that I'm interested in, but I'm not sure if it's the fiber optic fluid fillled transducer that's used. I understand that it can be the most accurate, it can drain CSF as well, but it's highly invasive and theres an increased chance of infection. Thank You, Christine