I recently purchased Flexisoft EB 17-3 toothbrush heads from a realiable seller. Because of the scam warning, I researched the OralB.com site and eBay products to see if there are differences in appearance of packaging and wording on the package. I was very surprised to find that every toothbrush head I had purchased was too big to fit my handle. The head looked exactly like my fitting toothbrush except the cutout for the shaft handle was obviously bigger. Unfortunatly, I always take the product out of the packages and store the brush heads in a plastic bag. My OralB is 4-5 years old and I have never encountered a problem before. I can only believe that the seller had unknowingly purchased knockoffs and I unknowingly purchased from him. I realized what had occured only because all the brushes were removed from the packaging and were tested at the same time. I did not want or ask for a refund, but did alert the seller as to what I found. I also emailed OralB.com customer service to advise them of the problem.