Most tape libraries, such as the Dell Powervault TL2000 and TL4000 have a slot on the top to insert their lockdown mechanism when transporting the unit. This is important so that the picker doesn’t move around and get damaged when moving the unit. This is especially import when shipping the unit. There is usually a little bracket in the back which houses the clip when your not using it. If yours is missing then you can make the one shown here from a paperclip.
Here is a picture of how you need to bend a paperclip in the event that you have lost your picker lockdown also referred to as a “Shipping Lock”
All that you need to do is fold the part of the paperclip where the double loops are down 90 degrees. You then have to place a strip of tape on top of it to secure it down.
Also, if you are shipping a tape library like the Dell Powervault TL2000 TL4000 or the IBM TS3100 or TS3200, make sure you pack it properly. Use a double walled box with re-enforced corners and fill the open spaces (at least 4″ on all sides with bubblewrap. DO NOT USE PEANUTS. Packing peanuts will move around and pieces may get stuck inside your unit and do some damage.