A manufacturing defect claim alleges a product deviated from the manufacturer's typical units. The deviation must render the product defective.When you have a defective product, it's important to know your rights. Call our product defect lawyer from Houston, TX to help you with compensation. A defective product is an item that's flawed in some way that makes it unsuitable to perform its function. All product liability claims require that the injured person prove the product was defective in design or manufacture, or that it had inadequate warning. To prove liability in the case of a defective product, the claimant must show: They used the product as intended. The product was defective. A defect in design usually means that the corporation that originally created the product would be the primary responsible party for your injury. 1. The product was defective at the time of the injury.