Sandisk Connect Wireless Stick 16GB

if you have downloaded any files other than pictures from the stick to the phone it will be stored inside the connect drive app. additionally there is some other data that is cached to the app that will increase the size of the app. 

in settings > about there is an option to clear cache. Try doing that and see how much space it frees up. if that does not help you can delete anything in the my downloads section of the connect drive app. if you are still seeing it take up a large amount of space you can delete the app and redownload it. this should make it the original size.