21" isn't very tall, except by then, hopefully your pup will know that s/he's supposed to stay behind the gate, not get over it. But they're very determined.
However, if you're looking for double-duty for a skin-kid down the road, it won't do at all. Babies would get over/around that gate in a tick-tock.
You'll need something more substantial, and a bit higher to use for both. |