What are the member countries under SAPTA?
Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan and Sri Lanka are the member countries of SAPTA.
What are products eligible for Tariff Concessions? And to what extend?
Tariff concessions were granted only for lists of products by each Member Country. Lists of products and Margin of Preferential (MoP) offered by all member countries are given at http://doc.gov.lk/index.php?option=com_content&view=article&id=61&Itemid=189&lang=en
What document to be submitted to the Customs Authorities in the importing country to avail the tariff concessions?
A Certificate of Origin issued by the DoC should be submitted. DoC issues CoOs only for the products which meet the Rules of Origin Criteria as given at http://doc.gov.lk/images/pdf/our_services/sapta/sapta_roo.pdf
You may discuss the eligibility of your products for tariff concessions with the Rules of Origin Division of the DoC.