This is possible because instead of using the traditional tanning bed lamps that are made using a phosphor coating, the bulbs used in high pressure tanning bed are made of different material. They use a ultraviolet light quartz lamps. These lamps are attached behind a rather expensive glass filter. The glass filter is so designed that only those ultraviolet rays can pass through which have a defined wavelength.
The term high pressure is used because the gases that are trapped in the quartz lamps are packed in at pressure which is more than the normal atmospheric pressure levels. On the other hand the lamps that are used in the traditional tanning beds are trapped at pressure levels that are lower than the normal atmospheric pressure levels. These high pressure tanning beds also come with a secondary filtering system that removes most of the rays of infrared spectrum.
The high pressure tanning beds need not be used twice a week. Within just three to five sessions, you would get a great looking base tan. After this you would only be required to use the high pressure tanning beds two or three times in a month or so.
While the high pressure tanning beds might seem a bit expensive in the first go, they are a new technology and very soon it would become equally affordable as the conventional tanning beds.