... .to DIN 18257/DIN 18273(fire-rated ) 3,200,000 test cycles 4,For fire door used Stainless Steel 304 Grade ... frequence of use for public building 200,000 test cycles High corrosion resistance With sliding bearing technology Surface: PVD Gold , Satin or ... and service are pretty faithful. HSK brand hardware is synonymous with Quality Stainless Steel Tube Lever handle