John:
If you or anyone in your family has bad knees or hip going to the quadra-step is a must.
If I remember right my 3 step had a rise of 9" to 9 1/2" between treads.
My quad has rises from bottom
tread-1 to tread-2 = 7"
tread-2 to tread-3 = 7"
tread-3 to tread-4 = 8"
tread-4 into camper= 8"
An inch or two don't sound like much but when your on bad knees it's a lifesaver.
C.B.