The Ambu Oval Plus Silicone Resuscitators has been constructed to use the Mark IV patient vale, the Mark IV inlet valve and the reusable oxygen reservoir. With the compatibility to Mark IV the amount of spare parts need to be maintained during the regular use. The resuscitators are semi-transparent allowing for a visual check of the patient’s condition. A pressure limitation valve is optional for the adult version and has been included into the design of the pediatric versions to ensure the safety of the patient.