This gate is one of the few gates specifically designed to contain cats. We bought it when we adopted to kittens and needed to gradually socialize them with our grumpy old lady. And it actually was able to contain them. It's 6 high, so they can't jump over it. And the bars are entirely smooth vertical rods, so they can't climb it. Standard child and dog gates will not contain cats.
The gate we're selling contains the gate itself:
https://www.petco.com/shop/en/petcostore/product/richell-white-cat-safety-gate-375-l-x-3-w-x-715-h-3817905
And an extension kit:
https://www.petco.com/shop/en/petcostore/product/richell-cat-safety-gate-extension-07-l-x-07-w-x-70-h-3747548