Sen. Jon Tester (D-Mont.) on Monday slammed national Republicans for mocking the car he uses to get around Washington: a red Toyota Prius.

“What a bunch of jackasses,” Tester said in response to a press release from the National Republican Senatorial Committee that called Tester’s choice of vehicle a “bombshell.”

Tester bought the Prius in 2020 and regularly uses it to get to and from the U.S. Capitol for votes in the Senate. It’s not the only vehicle he owns, however.

“I’ve got an ’86 Chevy. I got a 2018 GMC. I got a 2018 Honda Ridgeline. I’ve got a Celica. I’ve got a Peterbilt. I’ve got a ’67 International truck. I’ve got a ’96 International truck. I’ve got a ’78 GMC. Want me to keep going?” Tester told HuffPost on Monday.

“I’m gonna spend $10,000 this week on diesel filling my bulk tanks that I use for planting my crop in the ground. Does that make it OK now?” he added sarcastically.

NRSC spokesperson Maggie Abboud said in a statement, “There aren’t a lot of dirt farmers in Montana who drive a Prius. Jon Tester has gone Washington.”

Tester is a third-generation Montana farmer who is one of the Democrats’ most vulnerable incumbents this election cycle. Republicans are hoping to stop him from winning a fourth term in a GOP-friendly state by highlighting his ties to Democrats and President Joe Biden’s administration.

The red-state Democrat has sought to put distance between himself and Biden’s environmental agenda. For example, Tester voted to roll back the administration’s electric vehicle mandate for passenger cars and trucks, which aims to phase out two-thirds of new gas-powered cars by 2032. That GOP-led effort failed to get 60 votes needed to succeed in the Senate.

Tester is facing Republican Tim Sheehy, a former Navy SEAL and wealthy businessman, in November.