tender for frames for conc. plant , frame troughing idler -for 1000mm wide belt , drg 787 / 91 , at sl . no . ( 1 , frame troughing idler -for 1200 mm wide belt , drg- 787 / 91 at sl . no . ( 2 ) , self aligning troughing idler frame-for 1200 mm belt , as per drg- 788 / 91 , at sl . no . 2 , self aligning return idler frame with 2 guide roller for 1200 mm belt , as per drg no-592 / 87 , at sl no 2 , frame troughing idler for 1400 mm wide belt drg- 787 / 91 , at sl . no . 3 , self aligning troughing idler frame for 1400mm belt , as per drg-788 / 91 , at sl . no . 3 , self aligning return idler frame , belt width 1400 mm , drg- 592 / 87 sl . no . 1