The Quevis model has a short flap and more angled thigh block for
riders who ride with more bend in their knees or who have a longer femur.  Also works well if you ride with a longer leg. English stirrup leathers or western fenders can be added at an additional cost.
 

It weighs 10lbs alone, 12lbs with the
pad and inserts. The panels of a 17"
are 21.5", an 18" is 23".