Notes on the use of Pneumatic Fitting Pneumatic Fitting, also known as Pneumatic Quick Fittings or Pneumatic Quick Seal Fittings, is primarily used to efficiently seal jointed fittings in leak testing and is suitable for a wide range of sealing applications such as metal fittings, plastic fittings, coated tubes, and more. Although very practical, there are many precautions to take when using Pneumatic Fitting to maintain it for a longer period. Let's take a look at the precautions and benefits of Pneumatic Fitting. Here are some answers.