It is a breakthrough in Torts Law to impose post-sale duties on manufacturers after products had been put on markets. Post-sale duties are correction of development risk defense under strict liability. It has functions of preventing damage and protecting consumers. That manufacturers know or should know defect of product is the generating condition of post-sale duties. When defect emerges (before sale or after sale) does not affect the establishment of post-sale duties. The tort liability caused by violating post-sale duties belongs to fault liability, and cannot be defended by development risk. The statutes of repose on victim's right of remedy cannot be applied in suits on violating post-sale duties.