Over 730 square-feet of play area! The junction’s function is to allow children to make a “return trip” or to “transfer” from one tunnel to another! This non-threatening gross-motor activity comes with 1 junction and 4 tunnels that attach/detach quickly and easily for instant hide-‘n’-seek fun. Folds conveniently and compactly in seconds! Junction measures 18 1/2"H x 35 1/2" dia. and has a mesh center for visibility and ventilation. Institutional-grade tunnels are 18" dia. x 36"L. Wipes clean with a damp cloth. Use indoors or out. Polyester taffeta meets all CPAI-84 standards.