OEM or Original equipment manufacturer means the pack without manuals, instructions and faaltu maal etc. It only consists of the company manufactured item (headphones), and buds anc basic accesories etc. with the Original Manufacterer's Stamp on it. These are directly from Manufacturer without going to retails.
What in retail we get is Other faaltu samaan according to our locality, manuals etc. All these items are put in after the OEM are purchaised by them and then put in the market for Retail.
in my sight.. OEM Products > Retail = Less Chances of Tampering!