Gorilla Gym is lightweight, portable, easy to install and store. The core doorway unit is made of strong, lightweight steel that won’t bend or break. Gorilla Gym Kids package attachments are plug’n’play so they are fast and easy to swap out. The core doorway unit is certified to relevant ASTM International Standards and designed to hold up to 300 pounds. Gorilla Gym is safe and sturdy for kids and grownups too.