I just bought a quad with the Arctic Cat brand nerfs, they are identical to the pro armors. They have tons of foot room and don't weigh you down (aluminum). Nerfs extend about 1" past tires letting you shift weight outside of the wheels. Heel guard area is HUGE. Allows clearance for 24" tires on 10in rims with about 1" between the tire and the back of the heel guard just to give you an idea of how they fit.

I have some Cat ones on my DVX and think they are crap. I have 2 4 ' cracks that appeared under the heel guard. I contacted Cat and Pro Armor and got nothing. I would love a new set of Albas But the only style I really care for has been discountinued.