Fork Extensions are available with retainers.
Press Release Summary:

Original Press Release:
Fork Extensions with Push Block Spacer
Fork Extensions with Push Block Spacer is designed to make loading a pallet on the back of a truck more quickly and convenient. The spacer length is slightly more than
the jam of the truck door. Once you sit the pallet down you can close the trailer door; this eliminates the need to back out of the pallet a few inches, pickup the pallet again, and then push in to clear the door. The block also makes it convenient and practical to push pallets two or three deep into the truck.
These fork extensions are available with various retainers to keep fork extensions from sliding off of the forks. Lengths available are 48", 54", 60", 72", 84" and 96". These fork extensions will accommodate existing fork widths of 4", 5" and 6" that are up to 2" thick (OSHA states that the length of the fork extensions may not exceed over 150 percent of the length of the existing forks).
Also available are standard Fork Extensions as well as Round and Triangle Fork Extensions.