There's no handoff in product design because designers and engineers are not separated; instead, they work together from the start. This collaboration begins with understanding technical constraints early on to inform design decisions. Designers share rough prototypes with engineers and engage in discussions about technical feasibility, which can lead to a better product. As the product is built, designers work alongside engineers to refine their designs, ensuring a clearer perspective based on real data, technical constraints, and how the product feels. This approach requires empathy towards both users, clients, and engineers, leading to stronger designer-engineer relationships and ultimately better products.