Cotton cover hose fittings are commonly referred to as Reusable Hose Fittings, but are more accurately described as Field Attachable hose fittings.  It is not recommended to reuse these fittings.  They come in a two-piece configuration with the ferrule having a course reverse or left-handed thread that threads onto the hose, while the stem has a finer regular or right-handed thread that threads into the ferrule once the ferrule has been threaded onto the hose.