Knack is an upper limb prosthesis developed to provide economically disadvantaged amputees with an improved ergonomic and functional prosthesis experience. It uses 3D scanning to achieve a perfect fit by collecting a high-resolution model of the amputee’s body. The 3D printing method allows for a lightweight prosthesis with high dexterity, leveraging the flexibility of the additive process to create customized components with a personalized aesthetic. The prosthetic hand mechanism was simplified by using elastic thermoplastic polyurethane hinge springs at all the joints. Kinetic movement comes from a hybrid system with body-powered arm actuation and a motorized hand unit.