King Trellis (there when you need it gone when you don't !) - We Believe in making our best product at the right price, NO compromise ! -Retractable Barriers are ideal for doors, sliding doors, windows, shop fronts, offices, patios and most other openings that need security. -No plastic or nylon parts. -Single upright door manufactured from 19mm square tubing with a 1.6mm wall thickness.