This vintage Ingersoll Rand 231 air impactool is a powerful and reliable tool that has been tested and is in good working condition. The Ingersoll Rand 231 Air Impact Wrench Model A has a maximum reverse torque of 600 ft-lbs. It's a super-duty model designed for heavy-duty applications. The tool has a 1/2in. drive size and a 1/4in. air inlet size. The Ingersoll Rand 231 Air Impactool Model A was manufactured in the USA. While some later models, like the 231C, were made in China, the Model A was originally a US-made product. The company's early manufacturing plants were in New York.