Just a heads up that at ORD T2 the TSA Precheck line is closed while they are renovating the terminal (apparently Delta left it to move to T5). This means CLEAR in T2 is only for regular security. To use CLEAR for Precheck you have to go to T1. I just did it this morning. The Precheck line at T3 at 7am was full and on the verge of spilling out of the maze. When I saw that I turned around and walked over to T1 where it took me about a minute to walk through CLEAR and another 2 or 3 minutes for actual TSA screening, and then I walked back to T3 air-side. I have no idea if I saved any time over waiting in line, but at least I was moving the whole time rather than standing around in line.