Device for monitoring gear lever position

A device for monitoring gear lever position, which can be installed on bike, the device includes:

• an internal tube, which comprises of one ring-shape outer rim, one slot formed on the said outer rim of suitable position and one hollow and axial sheath for fixing bike handle, wherein, the outer diameter of the said sheath is smaller than the inner diameter of the said outer rim so as to forming a storage room between the sheath and the outer rim;
• on a suitable position of the said slot, there is a window going through and connecting between slot and the said storage room;
• an external tube is a hollow structure and surrounds on sheath, thus, the relative rotating motion between external tube and sheath is happened, there is a position ring for showing gear lever position installed on the storage room relative to the external tube, the said window is just above the position ring;
• and
• an transpicuous cover, which wraps inside the slot, and a fish-shaped lens is set on transpicuous cover, the fish-shaped lens is a convex lens, and the position for fish-shaped lens is designed on an imagine line which from rider's eyes to position ring, and fish-shaped lens is in between as well.