Google appears to be developing a new smart home product, according to a new Federal Communications Commission (FCC) filing for a wireless device.

Based on the few breadcrumbs Google sprinkled across documents logged with the FCC last month, it's likely the company is readying a new Nest smart home gadget.

As 9To5Google reports, mystery device G28DR—described as Equipment Under Test (EUT)—is certified for use with Bluetooth and Wi-Fi, but not other common connectivity options like NFC (near-field communication) or UWB (ultra-wideband). Google registered a total of seven exhibits with the FCC's Office of Engineering and Technology (OET): two cover letters, a label sample, radio frequency exposure info, and a trio of test reports.

One document—which tipped a 3.65-volt battery—describes connecting G28DR to a Dell laptop via USB, suggesting the EUT is chargeable through standard methods.

It's unclear exactly what Google is prepping, though. We can probably rule out any more Pixel products, the next generation of which were unveiled at the company's annual developer conference in May; and the Chromecast series is unlikely, considering the inclusion of a battery in this new product.

That leaves Nest—the smart learning thermostat and smoke alarm platform acquired by Google for $3.2 billion in 2014. A second-gen wired-only Nest Doorbell with 24/7 recording was confirmed last year, which leaves a new camera, thermostat, a speaker model, or perhaps a brand new type of device as possible options. The FCC paperwork requires device photos and the manual to remain under lock and key until January, so it could be some time before wwe find out exactly what type of device this is.