The ProSlide Series 2021 Belt Drive System is engineered to provide long life and quiet operation for commercial applications. The sliding door system features a 4.5-inch by 7-inch header capable of handling panels up to 250lbs in bi-parting systems and 300lbs in single slide systems. The product incorporates an adjustable astragal with a double weather seal in the lead rail of the sliding door panel for optimal condensation, air infiltration, U-values and improved energy efficiency.