supply of supply of air bellow duct set, each set of air bellow ducts , supply of air bellow duct set, each set of air bellow ducts consisting of : 01 no of supply air bellow duct, 02 nos. of fresh air bellow ducts & 2 nos return air bellow ducts. the bellow ducts should be made of meta aramid/para aramid fabric with silicon rubber coating on both sides and the metallic frames at both ends of the ducts i.e. rmpu side & coach shell side, shall be as per rdso specification no. rdso/ pe/spec/ac/0197-2020 (rev.-1) & rdso drawing no. rdso/pe/sk/ac/0069-2004 (rev.3), suitable for use i n rmpu of lhb type ac coaches. [ warranty period: 60 months after the date of delivery ] ]