Models View all Flange ___-__-01-1-B-St.20-IV GOST R 54432-2011 1 86 0 Concentric transition GOST 17378-2001 3 76 0 T-piece GOST 17376-2001 1 128 0 withdrawal GOST 17375-2001 1 36 0 Ventilation elbow 13 298 0 Ventilation duct 11 350 0