Oxygen masks these days are used in many different areas. These devices are needed to perform an oxygen therapy. And it is also impossible to fly modern fighting aircraft without an oxygen mask. There are different models of oxygen masks available starting from pretty simple modifications for everyday use in oxygen therapy to rather complex helmet systems for pilots. The main goal of any oxygen mask is to provide a recipient with the needed quantity of oxygen. That defines the basic models of oxygen masks and the parts it consists of. Although there are other modifications of oxygen masks, the most widely spread model consists of a mask looking device that covers both mouth and nose, the valves and tubing. Special indicators and a regulating device are not usually considered to be parts of an oxygen mask (most of the specialists consider these devices to be included in the oxygen supply system). As you can see, there are many different uses for an oxygen mask and a great number of these devices (in all possible forms and variations to suit different needs) are manufactured worldwide. One of the leading companies in these sectors is Gentex. Its respiratory products are known for their high quality. This company has a wide range of oxygen masks, but still the major part of gentex products are so-called HA/LP oxygen masks(High Altitude/Low Profile masks, they are designed to be used by pilots). The most popular models are probably the MBU series. This oxygen masks family includes devices with different characteristics and for different purposes. For example, usaf mbu 20 p HA/LP mask is intended to be used in "PBG"(which is "Pressure Breathing for G", that means that this mask will work perfectly up to the level of 60000 feet) attack aircraft. It is lightweight but very powerful. The tubing is equipped with side-entering oxygen valves, which help to lower the resistance to oxygen flow and, thus, increase the efficiency of the oxygen mask. Inhale and Exhale are separate in this mask which allows for an easier oxygen intake. By the way, in combat less tiredness can mean a lot. With a special protective system it can withstand a 600 knot wind. It is so good that all modern F-15 and F-16 fighting aircrafts are equipped with these gentex oxygen masks. It is designed in a special way so that to provide the pilot with a maximum field of vision. This oxygen mask model is available in three different sizes so that a pilot could choose his size. And now it replaces the older model of the family MBU 12 p oxygen mask. But it is not the only high quality product among gentex oxygen masks. The company also produces comprehensive helmet systems that include gentex oxygen masks in the set. They even have special gentex aircraft helmets and gentex oxygen masks that have been specially adopted for the Russian aircraft "MiG" and "Sukhoi". High quality and wonderful operational characteristics of gentex oxygen masks made them very popular in different countries all over the globe.