Corporate raider Carl Icahn has mounted an unsolicited bid to take control of Oshkosh Corporation, valuing the heavy-duty truck maker at roughly $3 billion.

Oshkosh, which is based in the Wisconsin city of the same name, makes tankers, fire trucks, and other vehicles for emergency services, industrial, and military clients. The company has retained Skadden, Arps, Slate, Meagher & Flom and Foley & Lardner as it evaluates the tender offer by Icahn.