The extender kit is needed on the Nissan Frontier with Utilitrack and bed extender. It does not install easily, and it took several hours by my dealer to get the cover on. The problem appears to be with the instructions for the kit. The bed extender central tubes did not slide when the brackets holding them were loosened. They were frozen, and I and the dealer service people couldn't unfreeze them to shorten by 4" as indicated in the instructions. It could be a new design feature involved. The dealer ultimately called for additional info on the extender. Apparently, there are (at least on new? models) inner tubes that give additional support. The external tubes do not slide. They had to cut the tubes by 2" on each side. Once this was done, the extender kit works as described.