Profile: Quantum Windows Ltd. specializes in PVC, and aluminum windows & doors. Our vertical sliders feature anti-jemmy security bars, reinforced sashes, all hardware are fixed to reinforcing, multi-chambered construction, and triple weather seals. Our bi-fold door is simple to operate using a bottom rail concertina mechanism. Our sliding patio doors are reinforced for strength, and have inner sliding leaf for security, internally snap fitting bead, and stainless steel tracks.