A quick guide to iSKU and CSKU in SelluSeller
iSKU (Inventory Stock Keeping Unit) is a unique code assigned to a product to identify inventory assigned to the product.
CSKU (Channel Stock Keeping Unit) is used while listing that product on various marketplaces (sales channels).
For Lazada Marketplace
iSKU = MBL001 is listed with CSKU = MBL001
For Zalora Marketplace
iSKU = MBL001 is listed with CSKU = MBLRED001
Hope this answers your question.