I have an original Wallytractor that was cut for my SME 3009 Series III arm. It is specific to that arm geometry and etched for it. It has the entire tonearm arc traveled cut to check the stylus is matching the geometry. When I got mine from Wally they were $100.
Previously, I used the Shure V15V-MR alignment jig for my arm and it worked well. The Wally tractor was just easier for me to use with my arm and turntable and provided more check points for the arm travel.
If you are trying to setup more than one arm, a universal alignment tool would be more flexible.