supply of supply of complete set of bellow duct.supply of complete set of bellow duct.,supply of complete set of bellow duct made of meta aramide fabric with silicon coating on b oth sides with metallic frames for lhb ac coaches confirming to rdso spec no. rdso/pe/spec/ac/0197-20 20(rev-0) or latest. material to be procured from rdso/pu approved suppliers only. one set duct is for 1 r mpu unit which consist of 1 no. of supply air bellow, 2 nos of fresh air bellow and 2 nos of return air bellow duct with metallic frames. out of total qty, 50 set bellow duct should be suitable for 3 ac lhb economy coa ch and other 50 set bellow duct should be suitable for 1 ac, 2 ac, 3 ac lhb coach. [ warranty period: 30 months after the date of delivery ] ]