Tesla (TSLA) shares gained Tuesday after Chief Executive Officer (CEO) Elon Musk announced that the electric vehicle (EV) maker will offer owners a free trial of the company’s driver-assist option.

On X, the social media site he owns, Musk said, “All US cars that are capable of FSD will be enabled for a one month trial this week.” FSD stands for the carmaker's Full Self-Driving system.

In addition, Musk reportedly wrote in a memo to employees that it’s mandatory in North America to install and activate FSD in newly purchased vehicles, and that buyers must be taken on a short test drive to understand how it works before they leave with their Tesla.

The move comes as the company tries to gin up sales with demand for EVs industry-wide slumping. Tesla has offered 5,000 free hours of Supercharging for customers who take delivery by the end of the month, and 10,000 free hours for owners who trade in their Tesla for a new one.

Tesla shares were up 5.3% to $181.81 as of about 11:30 a.m. ET Tuesday but have still lost more than a quarter of their value in 2024.