Last week, The Wall Street Journal reported that Walmart, JB Hunt Transportation Services, and Ryder System Inc. had placed deposits to reserve the first Tesla Semis. On Tuesday, German shipping company DHL announced that it, too, would place reservation deposits with Tesla for 10 trucks. This week, the WSJ also reported that reservation deposits for the Semi had jumped from $5,000 to $20,000.

The companies will be early adopters of the all-electric truck that Tesla announced in mid-November. On paper, the specifications for the Semi seem impressive—just last week, Tesla posted “expected prices” that exceeded expectations. The company seems to be targeting $150,000 for a truck with a 300-mile range and $180,000 for a truck with a 500-mile range, with both trucks due out in 2019. That said, those prices can change, and Tesla doesn’t have a great track record with meeting deadlines.

We also should remember that the specs/lineup of products can change, too. When the Powerwall was announced in 2015, Telsa offered a “backup battery” at 10kWh and a “daily cycle” battery at 7kWh. But the 10kWh battery was eliminated shortly after the company started delivering its batteries.

At any rate, a number of shipping companies are signaling their willingness to test out the truck when it rolls off the production line. Walmart, which has committed to eliminating a gigaton of emissions from its supply chain by 2030, ordered five Tesla electric Semis for its US fleet and 10 for its Canadian fleet, the WSJ reported. (Walmart has also experimented with other kinds of new technology like PowerPlug fuel cell forklifts.)

DHL said it was going to order 10 Semis. According to the WSJ, it plans to use the trucks for “same-day customer deliveries in major US cities,” while also testing the trucks for safety and driver comfort on longer hauls. Another Canadian Logistics firm, Fortigo Freight Services, also told the Journal that it had placed a reservation for one Semi.

Neither JB Hunt nor Ryder System Inc. specified how many Tesla Semis they preordered, but JB Hunt said that it would likely use the trucks to support local West Coast routes.

Along with the Semi announcement earlier this month, Tesla also said it was working on solar-powered “megacharger” technology that could be installed at transportation route terminals to allow a Semi to charge up to 400 miles in 30 minutes. If Tesla delivers, such a system might provide an incentive for more retailers and logistics companies to take the plunge on a couple of trucks to test out.

Of course, other companies are already building clean trucks, so Tesla has competition on this front. Cummins recently announced a 100-mile range electric truck with the option of an additional diesel generator to increase its range. UPS also purchased a number of short-range electric Daimler trucks to make local deliveries. Hydrogen fuel cell startup Nikola Motor Company has also announced a fuel cell-based semi, and at the Port of Long Beach, Siemens is testing out an electric catenary system for trucks to reduce port emissions.