Ventilator Circuits work in conjunction with a ventilator to deliver oxygen to the patient. Circuits are available in adult and pediatric sizes to deliver the right levels of oxygen to patients in different stages of life. An optional filter is also available to protect patients from viruses and bacteria in the air. Other accessories include carrying cases, replacement batteries, and wall mounts. QuadMed offers a large selection of Ventilator Accessories from top brands like Allied Healthcare, O-Two. and Smiths.