Final answer:
The Ashurst-Sumners Act is the legislation that stopped the interstate transport of prison products to protect free labor and ensure fair competition.
Step-by-step explanation:
The act you are referring to, which halted the interstate transport of prison-produced goods, is known as the Ashurst-Sumners Act. This piece of legislation was passed in 1935 as an effort to protect free labor and ensure fair competition by prohibiting the shipment of prison-made goods across state lines. It involved an amendment to the Federal Criminal Code (now cited as 18 U.S.C. § 1761) and falls under the oversight of the Interstate Commerce Commission. Though not mentioned in the provided information, this Act is connected to the broader historical context of regulating interstate commerce, much like other statutes such as the Interstate Commerce Act and the Mann Act.