Very convenient ruler, can save your time and improve work efficiency, convenient, practical, stylish, durable and cute,to bring surprises to the family.It is very small, cute and easy to carry.Since it is powered by solar energy, you can use this calculator whether you are indoors or outdoor, which is not only completely economical but also very convenient.Not only is it a ruler but alos is a calculator, and it also has a magnifying glass.