These are just like the regular play tunnels but are manufactured from materials that are a little tougher and can withstand being outside. (best-cat-art.com)
This unique cat window - seat gives your cat a fun play tunnel that offers a stimulating view while protecting your window blinds and your privacy. (thenoseprint.com)
You can get these in a variety of styles from simple three way tunnels like the Trixie Play Tunnel for RabbitsProsper Collapsible 3 Way Play Toy > to systems you can join together. (bunnyproof.com)