Swings, Gymsets and Playhouses help keep active children wonderfully occupied. From this kind of play children acquire coordination, good balance, and proper muscular development.. They also learn about playing safely and cooperatively with others. The structural timbers and bars in our sets are quality selected from exterior-use pressure-treated pine which is kiln dried to reduce warping. Corners are rounded for safety to reduce the chance of splinters. Hardware is plated to resist rusting and swing bearings are made of nylon for a long, "quiet" life. Also, our sliding boards are made of durable plastic for safety, comfort and quality. These swings sets and playhouses are not only built of quality materials, they are also built well. Wide bases prevent units from tipping over. Each is engineered and built with your child's safety in mind.