Humidifier Bottle For Use With Oxygen Sources Such As Concentrators Liquid And Gas. Drive?s Multi-threaded Lid Ensures A Secure Fit Every-time Preventing Leaks And Service Calls. Compatible With Oxygen Flow Up To 15 Lpm. Audible Back Pressure Alarm Activates At 6 Psi. No Aluminum Fitting In Stem: It Eliminates Shredded Aluminum Diffuser So Often Found In Lower Quality Models. Soft Plastic Diffuser Reduces Clogging Due To Mineral Build-up. Translucent Jar Provides Improved Visibility Of Jar Contents. Humidifier Bottle Lid Is Colored Green/yellow Making It Easy To Tell Patients On The Phone How To Change The Bottle. Bottle Has A 500 Ml Water Capacity. Bottle Fill Line Is Very Easy To See. There Are Finger Grips At The Top Of The Bottle Making The Lid Easier To Screw On/off For The Patient.