Like all StyleView products, the patio doors are meticulously crafted with the finest materials and workmanship. YKK AP® engineers designed these products for powerful visual appeal and years of security, energy-saving comfort and trouble-free operation. A two-point lock provides security, and an aluminum threshold is designed for high durability. Wide-track adjustable, corrosion-resistant rollers with encased bearings assure smooth operation. Four-point locks and exterior key locks are optional.