... , 8mm. 3.Plain,Serrated,I-shape Series 1 (pitch 30mm) steel grating is the most common type, its use are throughout the ... whole industry, The center distance of this series steel grating is 30mm, Which comply with U.S. standards,It has ... , walkways and drains cover, stair step and so on. Tooth steel grating can be used for wet, greasy areas, especially for offshore ...