Couldn't find the belt for our 20+ year old vacuum anywhere else. Found it quickly on this site and vacuum is back as good as ever.
Center post-left-for: asa/ada/aua71/7112
4-121l, center post 10-9/16 x 34-9/32, 71 series
Buy this part and as many parts as you like and pay only $9.99 shipping, within the Contiguous United States.