Major new Tesla product line -- not a car -- will be unveiled at our Hawthorne Design Studio on Thurs 8pm, April 30

A month ago, Elon Musk tweeted cryptically about an entirely new product line for Tesla. In a note sent to investors and analysts Tuesday, Tesla investor relations announced what the product line will be: a pair of new batteries.

"We have decided to share a bit about what we will announce on the 30th," Jeff Evanson, Tesla's VP of investor relations, wrote in a message confirmed by BuzzFeed News as authentic. "We will introduce the Tesla home battery and a very large utility scale battery. We will explain the advantages of our solutions and why past battery options were not compelling."

Reached for comment, a Tesla spokesperson declined to provide further details, saying only, "We'll share more information next week."

During a February earnings call, Musk mentioned Tesla's ambitions to extend its lithium-ion battery technology to the home-energy market.

"We're going to unveil the Tesla home battery, or the sort of consumer battery that will be for use in people's houses or businesses, fairly soon," Musk said. "We have the design done, and it should start going to production, probably in about six months, or so. We're trying to figure out a date to have the product unveiling, but it's probably in the next month or two months. And it's really great; I'm really excited about it."