Length of the tube
The first thing to consider is the length of the tube. It is generally around 6 feet. This refers to the length between the machine and the mask. Some sellers offer 10 feet hoses, but you can find4 or 8 feet models(they are rare these days).
You need to consider several sub-factors such as where is your machine. If it is close to you, then you can get a shorter hose. Keep in mind that the air will lose temperature as it travels through the tube, so getting the longest isn’t always the best.
Diameter of the tube
Here we have another factor. The diameter of the tube refers to the inner diameter. It is a smooth surface while the exterior can be ribbed or smooth as well. Ordinary models have a diameter of 19mm while slim models have15mm. There is also a 22mm diameter, but it is rare and commonly used on older machines. Keep in mind that you will need to change the settings on the machine if you change the tube diameter. You can also contact the seller or manufacturer to help you with that. New machines can detect pressure changes and apply correct settings.