I bought four and one piece was broken at the tip and replaced. The screw part was cracked even for one piece which was exchanged. After disassembling and removing the batteries I was using yesterday for battery replacement, the part of the screw at the tip was broken as well. There is no strength.
It is good to perceive vibration and shine out, but it will also shine even in bright places, so if you can, we want you to correspond not only to "vibration" but also "light intensity" if possible. It seems that battery charges will start.
Since it entered 2 pieces, it attached to the front wheels of two bicycles. It can be confirmed even while driving, so it's fun. It is not always blinking, it shines when you feel vibration, it is economical. However, because it is shining in the daytime, is there any other way to waste it?