Helium 10 tool that expands a single seed keyword into a broad list of related search terms, used as the counterpart to Helium 10 Cerebro's reverse-ASIN lookup. Where Cerebro reverse-engineers keywords from competitors' listings, Magnet generates keywords outward from one term a seller already knows describes the product.
The two tools are run together to build the master keyword list: Cerebro supplies what competitors already rank for, Magnet fills in adjacent terms competitors' listings may not surface. Amazon-specific tools like Magnet (or alternatives such as Sellerize) are required instead of Google/SEO keyword tools because of Amazon's transactional search intent.