The Hero Arm is a 3D printed, below elbow prosthesis with interchangable covers.

The prosthetic is the world's first clinically approved 3D printed bionic arm and in 2022 became the lowest cost bionic prosthetic on the British NHS. At the time of aquisition the average bionic limb cost £60,000, whilst the Hero Arm cost £10,000.

Advancements in 3D printing have seen a raft of affordable prosthetics released. Many of these designs, such as Project Daniel6 and e-NABLE7, are grassroots and open-source projects that are significantly cheaper than the Hero Arm. But while these designs have become lifechanging solutions for many, they provide a basic functionality that allows users to grip objects with a singular mechanical operation. The cababilities of the Hero Arm are significantly more complex than most affordable 3D printed prosthesis, enabling the user to perform actions that require delicate motor skills such as holding a makeup brush or a glass.

The arm is a bionic prosthetic, with electric motors powered by a rechargable battery pack. The arm is controlled throughh myoelectric sensors that register small muscle movements in the user's residual limb. The user can cycle through six grip modes, instructing the fingers to grab, pinch, high-five, fist bump and thumbs-up. Feedback is given by flashing lights and vibrations.

The ongoing development of the Hero Arm is exemplar of child-centred design and involving children in the design process. Early in the development of the Hero Arm, Open Bionics founders Samantha and Joel invited a group of children and young people with limb differences to feedback on prototypes, and to explore what their dream bionic limb would look and feel like. These co-design sessions early in the product's development resulted in numerous innovations, such as the development of 'Freeze Mode' - a button that fixes the fingers in place when gripping an object so that it cannot be dropped (a feature suggested by user Tilly Lockey).

Perhaps the most interesting outcome from the co-design process was related to aesthetics rather than function. The children and young people consulted indicated that they did not want to hide their limb difference with a lifelike prosthetic but would rather celebrate it with something fantastical. Live sketches of the co-design process record young users of prosthetic limbs dreaming of fingers containing lipstick, the power of robot super strength, or a completely customisable arm that they could theme along their favourite colours, films and books. The children's playful, proud and imaginative approach to their dream limb directly informed the aesthetic design of the Hero Arm, with a new emphasis placed on the bionic 'superhero' aesthetic and movement of the arm, and a range of fanstistical customisable covers, including collaborations with 20TH Century Fox and Disney (including the Marvel, Star Wars and Frozen franchises).