Requires a deep rack. The shelve attachement depth is adjustable. I'm using this as a pullout gtr pedalboard on Flyht Pro 6U Double Door Rack. For this rack case, the pro stacker is too deep for a level installation (even when it is adjusted to it's most tight range). For me this is not an issue since I wanted to have the shelve at an angle, where the front attachement is low and the back attachement is high. When installed in this way the shelve fits in a prefect angle for my purposes.