Breathing systems provide the final conduit for the delivery of anesthetic gases to the patient. The anesthesia equipment is dissected and explained part by part such as Anesthesia ventilator Pressure Regulators oxygen failure protection device (OFPD) Flow Valves & Meters Minimum oxygen/nitrous oxide ratio controller device (hypoxic guard). Oxygen failure safety device (shut- off or proportioning device). Modern Conventional Vaporizers the breathing circuits and Anesthesia monitor with parameters with colour figures and concerned electronic circuits. Low oxygen pressure alarm and disconnection of patient tubes. Adjustable Pressure-Limiting Valve (Pressure-Relief Valve Pop-Off Valve).