I am selling a used cough assist machine with filters, Respironics CoughAssit CA-3000. The pressure was checked; for inhale is 50 cm H2O and for exhale is -54 cm H2O. You will need a physician to set it up and show you how to use it if you don't already know how. Located in KS but will ship. Asking $900.00. If you need pictures,please contact me.