Total of 6 upright vacuum belts for Sanitaire upright vacuums that use a rounded belt (the belt is not flat it is round).
Santiaire belt 52100A, 52100B and 52100C.
Sanitaire upright professional and commercial vacuum models using a round belt include following:
S635, S645, S675
SC684, SC688, SC689, SC695, SC679, SC882, SC887, SC888
SC881, SC886, SC899, SC9050