Interestingly, these do not keep your hands warm...they just keep them from being cold.  When you are hiking, running or doing other things in the cold your hands tend to get cold and can really ruin an activity.  Gloves, however, can make  your hands overheat while doing physical activities.  These just keep your hands at a normal temperature so you do not even think about them.  They are knit and gripping is pretty much non existent.  But for running, walking, or hiking out in the cold, they are great.