Aspen PetŪ containment products give dogs the freedom they crave while keeping them safe and out of trouble in the absence of a fence. Trolleys easily configure for use with a single fixed object or in between two fixed objects. Great for camping, picnics and park outings. Keep your dog safely contained in the yard with this easy-to-install Tree Trolley by Aspen Pet. This Tie-out Trolley lets your dog run around a tree without getting tangled. Completely portable tie out system installs in seconds, just attach to any fixed object. Features super strong galvanized steel aircraft cable, coated with crack resistant vinyl. Made with the worlds finest hardware components. Rust resistant hardware.