Hi Shay,
Below link will be useful -
http://scn.sap.com/docs/DOC-34554
Material master data is transferred from SAP ECC to SAP CRM using middleware. The relevant middleware object is MATERIAL.
(Through T-code - R3AC1, select the MATERIAL middleware object. Once you open the object go to Tables/Structtures Within Object tab. Here you will see all the relavant tables of ECC from where the material master record is downloaded to CRM)
Hope this will be useful.
Thanks and Regards
DJ