Chevrolet will offer Class 4 and 5 versions of its Silverado for commercial users in fields such as construction, utility services, and first responders, the company announced at the Texas Auto Show.

Chevrolet will initially offer 4500 and 5500 Silverado medium-duty trucks as chassis cabs when the trucks go on sale in 2018. The company will release additional details about the vehicles later this year.

“The focus is really on commercial truck users,” said Sandor Piszar, director of Chevrolet truck marketing.

The Silverado 4500 and 5500 will be available in regular and crew-cab models, with 4x2 and 4x4 capability and a wide range of GVWRs and wheelbases, according to the automaker. The trucks will be available with optional OnStar with 4G LTE connectivity provided by AT&T.

All Silverado 4500 and 5500 models will be powered by a Duramax diesel engine and Allison transmission, Chevrolet said in a release. There are no plans to produce GMC versions, Piszar said.

The move comes as Chevrolet is expanding its commercial truck lineup. Earlier this year the company announced it will offer a Class 6 Low Cab Forward model. The company is also developing a medium-duty straight truck in a partnership with Navistar.