Technical documents required for COA for Exhibition purpose are :
i) A Cover letter to specify :
Name, place, address, exhibition date, and length of exhibition or offer letter to participate in the related exhibition.
ii) The Invoice and Air Way Bill (AWB) for importation by air or Bill of Lading (BL) for importation by sea should be made available.
Contact us for the complete procedure including related fees and charges.
Source : http://bit.ly/are-you-exhibitor