SolarCity's next big product will be a "solar roof" that's entirely composed of solar panels — a sleeker alternative to covering an existing roof in solar modules sometime after installation. The plan was detailed during a call with investors yesterday, with company chairman Elon Musk describing the offering as a roof that "looks way better" and "lasts far longer than a normal roof."

The roof will be integrated with one of Tesla's backup battery packs, potentially allowing a home to operate off of solar power round the clock. That type of tight integration between Tesla and SolarCity is one of the reasons Musk has been pushing forward with a merger. He first hinted at this integration when announcing the next steps in Tesla's "master plan" last month, and on the call yesterday, added that, "solar and battery go together like peanut butter and jelly."

"A huge market segment that is currently inaccessible to SolarCity"

The product is meant to help reverse SolarCity's declining panel installations by targeting a new class of customers: people who need a completely new roof. Musk said that people won't get solar panels installed if they know their roof will need to be replaced soon. "There is a huge market segment that is currently inaccessible to SolarCity," Musk said. The company says there are 5 million roof replacements in the US alone every year.

SolarCity plans to introduce its solar roof in "the coming months," alongside an additional product "focused on residential solar and storage."