Spring mechanism adds extra closing force to overcome air resistance on heavy walk-in doors Special high-lift cam system outperforms similar spring hinges Cam-rise action reduces gasket wear, even with irregular floors Built-in dwell holds door open beyond approximately 135 degrees Simple manual operation reverses hinges for use on right- or left-opening door These Kason 1248 Spring Assisted Hinges are a high-lift cam system that can be manually reversed to use on right- or left-opening doors. (1) Hinge; High pressure die-cast zinc with self-lubricating nylon cam; Mounting holes drilled and countersunk for 1/4 inch (6.0mm) flat head screws; Polished Chrome finish; US registered trademark 2,415,070. From the Manufacturer: Kason is a world-class manufacturer of hardware, accessories and supplies for the refrigeration, foodservice and truck body industries. We design innovative solutions backed by robust quality management to ensure exceptional products. From hinges, handles and LED lights to vinyl curtains, fabrication supplies and more, you can depend on Kason for solutions that help businesses operate more efficiently. Since 1926, the Kason brand has represented dependability and excellence.