This is a very well made product that is solid and beautiful to look at, BUT my little 8 pound Mini Schnauzer puppy quickly learned to climb over it. The horizontal bars allow it to be climbed like a ladder. So, I'm not exactly sure how that makes this dog suitable for "small to medium size dogs." Otherwise, it's very stable and adapts well to most any size opening that you would have. If you buy this product, I highly recommend training the dog to never place their front feet on the gate. A squirt bottle of water after telling them "off!" seems to work well. The optional rubber pads that stick to the bottom are a joke, the adhesive isn't nearly strong enough and they are falling off within a day or two of assemble. Fortunately, they don't really have a purpose so it's not a problem.