... recommended.Cross bar centers:any greater than 30mm is ok. with 50, 100mm recommended.Surface treatment:G - galvanizedP - paintedU - ... of steel grating is the most commonly used in projects with American, Australian, Japan standards are available. This kind of ... specify its type, length, width, quantity and surface treatment. 4. If any enquiries, please contact us. steel grill for door&window grates