These are the real deal.  AUTHENTIC Eureka belts for use with the Sanitaire's and any other of the older style uprights that have the belt running down the middle of the brushroll.  I have tried generic belts in the past and most have suffered from premature failure and "burnout".  Some have even cracked and broke as a result of the heat and friction created when the motor is running. It all depends on the type--and quality--of the rubber folks.  There is a reason manufacturers recommend sticking with genuine replacement parts.  Though generic belts/bags *may* fill the void, my experience has always been less than positive.  These fit my 30+ year old Eureka upright perfectly and make it run like new once again.  I also refuse to part with this machine because I firmly believe it outperforms many of the newer models on the market today.  What's more, the maintenance and design of these older vacuums are such that you can usually do the work yourself.  If you understand how these vacuums work and are mechanically inclined, they are virtually maintenance free.  There is literally nothing that can go wrong on these machines except the belt and the occasional light burnout.  I generally need to change my mine roughly every 2-3 months depending on use.  Also, carpets with tassels and loose threads wreak havoc on these things--get rid of them.  They are nothing but a nuisance anyway.  Overall, I'm quite pleased and hope that Eureka continues to make these available for the long term.