1. Age: 4-6 years old 2. Develop cognitive learning ability in English/digital and learn unlocking skills，to develop childrens logical thinking ability 3. Easy to switch, smooth and not hurt your hands 4. Bright colors and exquisite patterns 5. One-to-one correspondence between lock and key 6. Healthy PP material, safe and no smell, reject BPA 7. Lock size: 6.2x2.7x8 cm, key 7.3x3x0.6 cm
