Treads made of pressure locked grating, as per DIN 24531, with bearing bars 30/3 or 30/5 serrated, twisted cross bars Ø6 and pitch 11x76 mm or 30x100mm, special side plates 70/3 mm with eyelets (to (to be screwed on the stair carriers) and anti-skid profile, hot-dip galvanized as per ISO 1461 (DIN 50976)