The Thermally Reactive Advanced Protection (T.R.A.P.) Breather assembly protects the contents of your storage tank from airborne moisture and particulate contamination. It combines a high capacity 3 micron air filter with a deliquescent breather that dries itself when air is expelled from the tank. This self-regenerating capability of T.R.A.P. enables extended life. Keep your fluids clean and dry with a Donaldson Clean T.R.A.P. Breather.