The long peice that goes out the window

the long tube that carries the warm moist air to the outside thru the window .. has to be kept clean inside ... if it gets clogged with lint then the dryer will no longer work correctly ... the tube should be removed and cleaned each year or so ... you can also just replace it ... they have several types at most hardware stores .. on the outside of the window should be a flapper valve .. that opens only when the dryer is running .. otherwise it closes to prevent weather leaks and animals from getting in .. that should be cleaned or replaced also once in a while .. the hose is eather 3 inch or 4 inch diameter .. you can snug it up with a hose clamp designed for your size .. that will prevent it from coming loose .. smooth inside pipe is best but the metalic extendable hose is acceptable .. the plastic hose is less desirable .. the smoother the inside the longer it will last before becoming clogged ..