With the specially designed extra loss-proof structure among the light line and green cones, these string lights are not only soft but also firm enough to twine and store easily without worrying about loosening issues which are commonly existing in the operation of other competitors. IP44 waterproof rating with the battery box, proper protection is recommended on a rainy day. Recommend well twined after using for the next time. The length of the working period depends on the batteries you applied. These string lights are not extendable.