In a newsletter update sent to existing Tesla owners late Friday evening, the Silicon Valley automaker and energy company announced that it will be adding a red ‘Founders Series’ Powerwall 2.0, hand signed by CEO Elon Musk, CTO JB Straubel and Chief Designer Franz von Holzhausen, to its latest Referral Program prize list.

Updated: Tesla invites winners of the ‘Founders Series’ Powerwall 2 to redeem their referral program prize

Existing Tesla owners who refer seven or more qualifying Model S or Model X sales will receive the company’s updated home battery storage unit that boasts double the energy storage capacity and a slimmer design than its 1.0 predecessor.

The update from Tesla reads, “We’ve made some exciting updates to our referral program awards. Owners with 7 or more qualifying referrals will receive an exclusive red Founders Series Powerwall 2.0, hand signed by Elon Musk, JB Straubel, and Franz von Holzhausen. This award is not available for purchase. Just share your personal code with friends, family, or anyone else. They can use the code to get a $1,000 credit towards a new Model S or X until January 15, 2017.”

Tesla debuted Powerwall 2.0 alongside its glass solar roof tiles October 28, 2016 as part of the company’s goal to provide a comprehensive suite of products aimed at solar-generated renewable energy and storage via batteries. Powerwall 2.0 is designed to allow homeowners to store electricity generated from solar, or through the utility grid when rates are low, for later use. The home battery storage unit also allows homeowners to leverage it as a source of backup power in the event of a complete power outage.

If you’re considering solar for your home or business, we encourage you to get a solar cost estimate first, based on your monthly utility bill and location. The service is being provided by an affiliate partner and fan to Teslarati.

Editors’s Note: The feature photo depicting a red Powerwall 2.0 is an artist’s rendition and not an official version being offered by Tesla.