Principles of communications: Systems, and similar items

This estimate is based on:

• The seller's handling time
• unspecified transit time to US

Actual delivery times may vary. Have shipping questions? Contact the seller

You can make your offer during the checkout process as long as you do not live in a state where marketplace facilitator tax laws exist. Check your state. If you are on a mobile device, please message the seller directly to submit your offer.

My store always accepts Free Return if you recognize something wrong/different between the actual items and their description. For example: the description says “size L” but the item you received is “size M”. Or different color, out of function, etc…

I offer 30 days money back, or exchange for those cases mentioned above.To be eligible for full refund, returns must be in the same condition in which it was received. It must also be in the original packaging. In case of missing packaging or items are not same with when you receive, the amount of cost will be deducted into the refund.

Also, If you decide to return an item simply by changing your mind or ordering an item by mistake or the item can’t fit you (please read the description about the size and measurement carefully before placing order), YOU will be responsible for:
- Return shipping costs.
- Closing fee for the transaction
Please contact me to know the total cost of the return

The return policy for books: same with the other items. If you recognize something wrong/different between the item’s description and actual books you receive, my store offers FREE RETURN for these cases. You pay NO COST for that transaction if the mistakes come from my store.
In opposite, If you decide to return books simply by changing your mind or ordering books by mistake or you don’t read the description carefully about the item’s status before you buy then you want to return it because it is not like what you think; or you want to return it after reading it and don’t like it, YOU will be responsible for:
- Return shipping costs.
- Closing fee for the transaction
Please contact me to know the total cost of the return

The refund will be proceeded after the returned items are checked and will follow the marketplace’s time frame.