In a counteroffensive filled with driver testimonials, expert witnesses and a highly produced video, Uber on Thursday filed a motion in a California court to oppose the certification of a class-action lawsuit that spotlights the work status of drivers for the ride-hailing service.

The plaintiffs assert that they are employees, and they are seeking reimbursement for expenses and what they say were improperly withheld tips.

The case speaks to the heart of Uber’s business model, in which the company treats the more than 160,000 people who drive for the service in the United States as independent contractors. The classification means Uber does not need to pay drivers’ payroll taxes or apply minimum wage and overtime laws to them. It also lets Uber bypass paying for benefits like health care or vehicle upkeep in some states.

In its motion, Uber said that its driver base was incredibly diverse and that the handful of drivers who filed the lawsuit should not represent the wishes of the whole.