... made of zinc powder-coated steel.3)The frame is strong,durable,light in weight,not easy ... ,coreboard,ABS-board.Applications:Party,outdoor wedding,outdoor exhibition,trade fair,celebration,sports event,military solution,temporary warehouse ... workshop.What need to mention:1)No pole inside,space can be 100% utilized.2)Easy to set ... /Steel nail/Loading system. 15x40m large aluminium frame tent for events