Length: 18 feet long; User can set it up to be shorter than 18' without affecting function

Opening: 24" in diameter, meets NADAC and AKC 24" opening specifications

Material: made of tough 210D waterproof nylon; 210D nylon is among the toughest nylon material on the market right now. It is durable, tear resistant and static free.

Rings are made of steel (not plastic), which keeps tunnel in perfect round shape, and will not break.

Black color patches are stitched along both sides of the tunnels, so you can put stakes through them to loop the tunnel around into any shape you want, and to keep the tunnel steady on the ground.