Just went thru the Dexter shoe
dilemma, here's what they told me.
The 12'' shoes are visually identical, the composition of the friction material being the only difference. Supposedly the 7k is more aggressive, with a higher concentration of the metal stuff.
I've been in the field a long time and they looked and felt exactly the same, I checked out both at the RV store.
Went with the 7k for our Classic.
"Sticks & stones can break your bones...and hail will dent your Airstream"
So when is this..."old enough to know better" supposed to kick in?