UB-9 Belt fits Uprights V7500 series, dual sweep vacuums.  Two (2) belts are required (1 each UB-9 and 1 each AC28SBFHZ000) for these vacuums and  both should be changed at the same time.  The UB-9 is the stretch idler belt.  Order the AC28SBFHZ000 which is the reinforced flat drive belt.  UB-9 is also the #MC-V350B package of 2 UB-9 belts.