The working life of a more recent Cohrs prototype (using various polymers instead of silicone) was still limited, according to reports in early 2018, with that model providing a useful life of 1 million heartbeats, roughly ten days in a human body. At the time, Cohrs and his team were experimenting with CAD software and 3D printing, striving to develop a model that would last up to 15 years. "We cannot really predict when we could have a final working heart which fulfills all requirements and is ready for implantation. This usually takes years", said Cohrs.