notice to buyers:

1. The goods in this store are genuine and the price is reasonable, and the goods will be fully inspected before shipment; There will be no quality problems; For example, due to the negligence of the staff, the quality and delivery of the goods are wrong, all are replaced free of charge; Please rest assured to buy.

2. The goods in this store are taken by real people in kind, and there is no false. What you buy is exactly the same as what you see in the picture; Quality problems refer to the loose button of the product and the black screen. However, situations such as color, workmanship and imagination are not regarded as quality problems. Please ask more questions before purchasing; Leave less regrets. If you can't accept less color difference problems, please purchase with caution!

3. Return and exchange issues:
if the product is not suitable, you can exchange it. The return shipping fee is borne by the buyer, and the return is the same (everything is the buyer's reason, and the buyer needs to bear the return shipping fee); For example: Wrong delivery, quality problems, return or exchange, the return freight shall be borne by the seller (everything is the seller's reason, the seller needs to bear the return freight).

4. Please don't forget to comment after receiving the goods! I hope you can be satisfied with our work! If you are satisfied, please tell your friends,
I hope I can also call them to experience the fun of online shopping!!! If you are not satisfied, please contact the owner. The owner will solve the problem for you in a timely manner. Misunderstandings often come from untimely communication. Please also respect the owner's labor and do not make a moderate or negative comment easily! That will not solve any problem. The store will complain to all buyers who give medium or poor reviews without saying a word. Please understand each other and pay attention to your comments. Thank you

5. Product receipt! When signing for the goods, please be sure to check whether the quantity of the products is correct, whether the products are complete, and whether the products are damaged on the spot in front of the courier...... If you find any problem, please reject it on the spot; Please sign for it after confirming it is correct!

Steps/methods

1. replace the battery in time: when the displayed reading is dim, it indicates that the battery has been exhausted and should be replaced in time. If it is not used for a long time, the battery in the machine should be taken out to prevent battery leakage from damaging the calculator.
   
   
   
    
2. Prevent squeezing: knock or drop on the ground: whether it is a calculator displayed by a fluorescent digital tube or a calculator displayed by a liquid crystal display, its display parts uniform and easily broken glass devices should be squeezed or dropped Strictly, to avoid damage.
   
   
   
    
3. Pay attention to the use environment: the liquid crystal display calculator can only be used in the temperature range of 0-40 degrees Celsius, and it is not suitable to be used under strong light, because ultraviolet rays in sunlight will accelerate the aging of the LCD screen. It is also not suitable for use and storage in humid and corrosive gas environment to avoid damage to parts.
   
   
   
    
4. Pay attention to dust prevention: after use, put it into a leather case or within plastic jacket to prevent dust intrusion. If there is dust on the panel, wipe it gently with a soft cloth. Do not wipe it with gasoline, ethanol, banana water and other chemical tests.
   
   
   
    
5. If the external power supply is used, its pole and rated voltage shall conform to the requirements of the machine.