4-wall PC sheet Application: general construction material process skylights of skyscrapers, department stores, gyms, fast food restaurants, churches, and hospitals arch skylights of parking lots, shopping malls, airports, swimming pools, supermarkets, and countryards reception rooms, usher offices, , jewelry stores, gas stations, booths, clock and watch stores, display windows soundproof facilities of freeways, MRTs, and overpasses heat-resistant sheets of greenhouses, factories, garages bulletin boards, shop sings, and indicators ceilings, light and lamp covers, shower stall doors, and skylights of offices insulation for electronic parts