If you look on the outside of the case under the bottom of the keyboard, you will see a hole. You can put a bolt of the correct length and thread size through the hole and it will screw into a hole on a metal part of the tty inside the case. I had an ASR33 shipped with the shipping bolt in place and it worked fine when it arrived at my place. I have had another one that was shipped without the shipping bolt and something inside seems to be out of alignment and the keyboard isn't working. Ashley