Last week we reported on a new cochlear implant that was designed to integrate in special ways with an iPhone. This week, Steven Levy has more details for WIRED on the work that went into bringing this product to fruition.

To solve the huge problem of streaming high-quality audio without quickly draining the tiny zinc batteries in hearing aids, Apple had previously developed a new technology called Bluetooth LEA, or Low Energy Audio. The company released that (but didn’t talk about it) when the first Made for iPhone hearing aids appeared in 2014…“We chose Bluetooth LE technology because that was the lowest power radio we had in our phones,” says Sriram Hariharan, an engineering manager on Apple’s CoreBluetooth team. To make LEA work with cochlear implants he says, “We spent a lot of time tuning our solution it to meet the requirements of the battery technology used in the hearing aids and cochlear implants.” Apple understood that, as with all wireless links, some data packets would be lost in transmission—so the team figured out how to compensate for that, and re-transmit them as needed. “All those things came together to figure out how to actually do this,” says Hariharan.

This story perfectly demonstrates how solving accessibility issues may require a lot of hard work and investment, but in the end it can produce results that are truly life-changing.