I know these aren't intended for long-term use, and presumably not in ambulatory patients, but still, this passage gave me a tremendous amount of range anxiety:

> Patients will wear a 4-kg external controller pack that contains two rechargeable batteries (providing about 5 hours of operation each), although they can also plug in directly to a power outlet.

Like, the stress of finding a free outlet when I'm on 7% charge is already bad for my heart