A backlight module is disclosed, which includes an outer frame having a sidewall and a hole formed on the sidewall, an inner frame disposed inside of the outer frame, and an adhesive device. The footrest is pivotable relative to the seat plate between first and second positions. The shaft is coupled to the buoy such that when the buoy moves vertically in response to a passing wave, the shaft rotates. The coil positioner is spaced from the belt by a predetermined distance.