The video explains the sizing and measurement nuances of speed rail, a common material used in the film industry's grip and rigging departments. Speed rail, often referred to as inch and a quarter or inch and a half, does not correspond directly to those measurements because pipe is measured by internal diameter, originally intended for fluid transport. For instance, inch and a quarter pipe typically has an outside diameter of about inch and 5/8ths, and inch and a half pipe has an internal diameter close to inch and a half.
