Amazon Product Advertising API Developer's Manual page 52

Product Advertising API Developer Guide
Each of these accessories has an item ID, such as an ASIN, as shown in the following response snippet.
In this example, the main item, B00008OE6I, the camera, returned in the response comes with two
accessories, B00003G1RG, a compact flash card, and B00004WCCT, a leather camera case.
<Item>
<ASIN>B00008OE6I</ASIN>
<Accessories>
<Accessory>
<ASIN>B00003G1RG</ASIN>
<Title>Viking 128 MB CompactFlash Card (CF128M)</Title>
</Accessory>
<Accessory>
<ASIN>B00004WCCT</ASIN>
<Title>Canon Soft Leather Case for Canon Digital ELPH Camer
as(Black)</Title>
</Accessory>
The following figure shows those items.
As you can see in this example, Amazon groups accessories with the main item for sale. Product
Advertising API makes it easy to retrieve all of the accessories associated with a main item by using the
Accessories response group in an ItemLookup or ItemSearch request. As you can see in the previous
response snippet, each accessory listed in the response includes the accessory's title and item identifier,
such as an ASIN.
Note
When you have the item ID of the main item, the Accessories response group returns the item's
accessories. The reverse, however, is not true, that is, if you have the item ID of an accessory,
you cannot use the Accessories response group to return the main item or the other accessories
associated with the main item.
Related Items
The RelatedItems response group returns information about items related to the one specified in an
ItemLookup request. The item is specified in an ItemLookup request. Digital items include downloadable
Related Items
API Version 2011-08-01
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