Of all the factors to consider when choosing an advanced prosthetic arm, the most important may be weight. Weight isn’t always top of mind when comparing devices. Features like appearance, durability, grip strength, and battery life usually come first. But when it comes to a bionic arm, weight equals comfort, and comfort equals usability. And above all else, you want to make sure that once you have a new upper limb prosthesis, you use it.

This survey of 200 articles on prosthesis use and abandonment found that up to 45% of amputees wind up rejecting their electronic prostheses. That rate is even higher among children, with one study observing a pediatric abandonment rate of 81%. Why would so many people stop using their prosthetic limbs? The reason that tops every list is excessive weight.

Some of the most popular myoelectric prosthetic arms weigh in at over three pounds. For context, that’s the weight of over seven iPhones. When you think about living life with that much extra weight at the end of your residual limb, it’s easy to see why weight can become an issue. Passive prostheses can solve the weight problem, but they wind up sacrificing form and function in the process. But these sacrifices don’t have to be made. At an ultralight 1.5 pounds, TrueLimb is half the weight of most advanced prosthetic arms. This keeps the comfort factor high, and makes it far more usable. In short, it’s a prosthetic arm that eliminates weight as an issue.

With its multi-day battery life, unprecedented level of personalization, and revolutionary price, TrueLimb is more than a device — it’s designed to be an extension of you. But that promise is only realized because we keep weight at the core of every design decision we make.

Want to see TrueLimb in action? We made this quick video to show you why weight truly matters.