1. The screw type is designed, is receives a track in vogue, is monstrates preeminent quality with fad;
2. Improve the water-proof function, the life time having increased a product's;
3. Take level readjustment to increase the high device, if the bottom box has when burying in advance when inclination or the fault is deep, but the interface carrying out appropriate adjustment, using entire installation thereby tends to beautiful expert;
4. The minor outgoing line adopt centre Kaikong when fixing outgoing line is assembled conveniently;
5. The hurricane band is opened inserting be in usage time, upper cover dyadicly open up, can cover usage at the same time, upper cover is not easy to be abandoned.