Trumpy, EMT (Electrical Metallic Tubing) is also some times called thinwall conduit. It is made from steel in 1/2" through 4" trade sizes. It's also available in aluminum in 2-1/2" through 4" sizes. The aluminum is much lighter and is easier to install in the larger sizes. The downside is that there's a lot more surface friction with the aluminum, so pulling wire in takes a lot more lube, power, or both...S
