It is best NOT to rely on Amazon for data for the products that you sell. Amazon restricts what data is available to download because of copyright restrictions (in the case of descriptions and images) and other API limitations.
Data Amazon Provides
SKU, ASIN, price, quantity, condition, condition note
Main product image
When available: brand, manufacturer, model number, dimensions, weight, UPC/EAN/ISBN
Data Amazon Does NOT Provide
Product descriptions (unless you wrote it - otherwise, descriptions are copyrighted by Amazon)
Product features ("bullet points" #1 - 5)
Additional images and high-resolution images
Restock date, handling time, sale price, search terms