My coach has 28" whipers.. I got one Trico Perfect fit for 10 bucks less change.
Now, as you might suspect, it did not fit.
The reason it did not fit has to do with how the whiper blades attach to the arm,, On my Workhorse there is a pivot pin which is a bolt with a Nylock nut.
On the perfect fit said pivot pin was a rivet already in place with a plastic adapter over it.
I grabbed ye old Dremel hand grinder and the Rivet went by by, enlarged ONE of the holes (the small one) left behind and the pivot bolt fit perfectlly..
It is installed now.