As of September 1, 2016, brand Neutral packaging is no longer offered by Amazon. All FBA multichannel orders ship from Amazon in Amazon-branded packaging.

Brand Neutral packaging was an option that Amazon FBA provided for multichannel fulfillment orders where they would ship your order in a blank package instead of an Amazon-branded package.

Source: http://www.amazon.com/gp/help/customer/display.html/?nodeId=201101040