Join Date: Aug 2006
Location: San Francisco Bay Area
Submit Photo: 5
Photo Submissions 18 Times in 12 Posts
They are pretty much all the same size in length. You just customize it to how much space you have/need. (You can overlap panels to make it smaller.)
The height preference varies by dog and your needs. 24" is a standard height, but if you have a climber, they can easily get over 24" with a little assistance (and some Havs don't need any assistance to climb that height). 36" is the next height, but that one is a little more difficult to step over, so you might want to consider an ex-pen with a walk through* door. 48" is the next taller size.
*Not all ex-pens that have doors are of the "walk through" variety. Some of them still have a bar across the top you will need to step over.