Yes, we welcome sample order to test and check quality. Mixed samples are acceptable.

Samples for 2-3 days. Bulk production time needs 4-5 weeks accoridng to order quantity.

For samples, 100% advanced.
For bulk order, 30% advanced, 70% against the copy of BL.

Yes. Please inform us formaly before the production and confirm the design based on the sample.

Yes, we offer 12 months warranty for our kit. And some components could be longer accorindg to its characteristics.

Firstly, our kit were produced with strict quality control system. 
Secondly, if there are defetive items were found, we will fully refund the cost of the items to you. Or we can discuss other solution with the real situation.