I got tracker 18.5 targa, it has the locking seats, bought it new in 05, now I am having trouble out of them, they are wearing out, it has been used almost every week since it was new, some times twice a week. The adjusting part keeps breaking, Can't find any just like them, went to bass pro and they told me to look for after market ones, I need two seat bases that will fit a 2 3/8 inch post. I found some on the INTERNET that will work, Springfield makes them, locking and none locking. Some of this tracker stuff is cheap made, I like the Springfield bases better, made better and stronger.