New Developed Butterfly Mechanism：there are four positions of XL, L, M and S which can be adjusted to fit children with different heights and growth rate
Multi-angle self adjustment system: shoulder straps not easy to slip off and more fit with shoulders
Ergonomic aluminum alloy bar
6° inclination towards the user’s back tilts the schoolbag’s contents forwards and transfers the schoolbag’s center of gravity closer to the user
Wing-shaped base plate：school bag not easy to fall down
