As self-driving technology company Aurora goes all in by buying sensor company Blackmore, Tesla (TSLA) CEO Elon Musk called the use of lidar for autonomous vehicles “freaking stupid.” Musk criticized the sensor technology as he was unveiling his plans to have 1 million self-driving robotaxis in Tesla’s portfolio of self-driving vehicles.

Aurora’s purchase of Blackmore was made for an undisclosed amount and will allow the company to integrate lidar systems to navigate through traffic by measuring a vehicle’s distance from obstacles such as cars, drones, and more, CNBC reported.

According to Chris Urmson, Aurora CEO, the use of lidar can offer greater vision, uses less power, measures velocity instantly, and is not as affected by poor weather. “Lidar is critical for developing the safest and most reliable self-driving system, one that can navigate our roads more safely than a human driver,” Urmson said in a statement.

Musk disagreed about the use of lidar saying in April, “In cars it is freaking stupid. It is expensive and unnecessary. Once you solve vision, it is worthless.”

Tesla uses a range of cameras to visualize the roadway and send data to the vehicle’s computer, allowing for navigation in traffic while lidar uses sensors that can see around vehicles, helping self-driving cars maneuver through traffic.

Aurora is not the only company that has a strong belief in the viability of lidar in autonomous vehicles as Google’s Waymo, General Motors, and other automakers have invested in the technology and are making headway with development and testing, the news outlet reported.

Shares of Tesla stock were down 1.58 percent as of 10:32 a.m. ET on Friday.

Tesla Elon Musk Elon Musk, co-founder and CEO of American electric vehicle manufacturer Tesla Motors, poses with a Tesla during a visit to Amsterdam on January 31, 2014. Musk reportedly fired his employees through an email sent at 1am. Photo: JERRY LAMPEN/AFP/Getty Images