More parties than you might expect. Under California's strict products liability, everyone in the chain of distribution that put the product in your hands can potentially be responsible — the manufacturer, any component maker, the distributor or wholesaler, and the retailer that sold it, even a seller that did nothing wrong itself.
This gives an injured person more than one path to recovery, which matters when a manufacturer is overseas, out of business, or hard to reach. In those situations, the distributor or retailer may still be responsible, so a claim is not necessarily foreclosed just because the maker is unavailable.
Identifying every company in the chain — and any maker of a defective component — is a core part of a product case. It protects your ability to recover and ensures the right parties are held responsible, which is part of what an attorney investigates early.