Tubex 4 Tree Shelter, 25 pack UV-stabilized polypropylene co-polymer Laser line to prevent tree strangulation Seamless twin-walled construction with strengthening rods built in for extra wind resistance Continuous scrape-free flared rim Preinstalled, releasable, nylon, ratchet-locking fastening ties and mesh netting to prevent songbirds from being trapped in the treeshelter