Uni-Suction can be operated both pneumatically by oxygen or manually by hand or foot. Wide base and low profile, provide for stability during use, Solid construction allows it to be used under adverse conditions in most climates. No regular maintenance. i.e. no lubrication or battery change needed.Always ready for use. Vacuum limiting valve reduces negative pressure to 150-200 mm Hg for tracheal suction and use on small children. High performance. Max. negative pressure up to approx. 550 mm Hg. Free air flow 20 l/min. (mean value).