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°. Simple manual operation reverses hinges for use on right- or left-opening door. Kason 1249 Series Reversible Cam-Lift Walk-in Hinge with Flush offset Chrome Finish NSF Approved Model No. 1249-01, Drilled and countersunk for 1/4" (6.0mm) flat head screws.