Topgrading Interview is between 2-3 hours and they dig deeply into your past starting in high school and working through all of your jobs. You take a little break and they get some more questions for you and that last about 30 min after and then it is finished

I had an initial phone interview and then what is called a top grade interview. It can take anywhere between 2-4 hours depending on the job. It is the most intense process I have seen for a job.