Service types
1. Paid Service (A) –Son-tech charges service expenses when maintains the products Son-tech has sold to customers.
 
2. Agreement Service (B) – Son-tech charges service expenses according to warranty agreement when maintains the products Son-tech has sold to customers. 
 
3. Free Service (C) – Son-tech charges no service expenses in the warranty period when maintains the products Son-tech has sold to customers.
 
4. General Administrative Work (D) -- Son-tech charges service expenses when does the general administrative work, such as routine checking, parts management, tools maintenance and other works which are not included in the former three terms.