... style , Serrated style , I section style4) Bearing bar specification:- Plain Type and Serrated Type Bearing Bar: 20 x 3mm to 100 x 6mm ... 3mm, 50 x 7 x 4mm, 55 x 7 x 4mm, 60 x 7 x 4mm, 65 x 7 x 4mm, 70 ... x 7 x 4mm, 75 x 7 x 4mm, etc.5) Bearing ... , 100 & 101. 6mm etc. and 50, 100mm are recommended .7)Main usage: stair trends, trench covers, drainage pit covers.