Silicon Valley start-up Aeva has been secretive about the technology it's been building to help self-driving cars understand what's happening around them.

On Monday, the company finally revealed its creation: a system that detects velocity, depth and reflectivity more than 200 meters away, without using a ton of power — in a unit that's the size of a tissue box.

If you think Aeva's simple white product looks like something Apple might make, there's good reason. The start-up's founders previously worked at Apple, specifically on its secretive car project that goes by the code name Titan. And like Apple, Aeva has even pursued development of a custom processor to complement other chips it uses.

With around 50 employees and $45 million in funding from investors including Canaan Partners and Lux Capital, Aeva is still a small outfit. But it's working with a handful of big-name automakers on integrating the product into various types of vehicles, said Soroush Salehian, who co-founded Aeva with Mina Rezk. A customer can employ as many as five of the boxes on a single vehicle, depending on the level of automation that's desired, with each unit costing $200 or $300, Salehian said.

Aeva's boxes won't be performing the self-driving computing. Instead, they collect lots of data, which can then inform autonomous driving systems.

Various types of competing technology is being built by companies like Luminar, Quanergy, Valeo and Velodyne. But Aeva is hoping that by packing so much into a tidy package — with even smaller versions expected in the future — its technology will stand out.

Correction: An earlier version of this story said the system worked from 200 yards away, instead of 200 meters.