14ft Trampoline with ASTM Approval and Galvanized Anti-Rust Coating, Outdoor Trampoline for Kids and Adults. Jumpking 14' Trampoline Combo! This round trampoline is great for children and adults, because it provides plenty of room to exercise. The patented T-connector provides more stability to the trampoline frame while jumping. The trampoline frame is constructed of rust-resistant galvanized steel, providing fun for years to come.