60 days return. Buyer pays for return postage. If you use an eBay delivery label, it will be deducted from your refund amount.
Condition:
NewNew
The essence of mathematics is logic. Human thinking naturally accepts the formula of "because" and "therefore.". Under such condition, it is impossible to succeed without diligence. If you are not diligent, you then will not have the chance to prove whether or not you are gifted and genius.