I believe this in not a genuine Dyson part. The genuine part is # DY-904174-01. Sells on here for about $5.00 more. All genuine Dyson parts start with DY. I made the mistake of buying a want-a-be roller brush from a different site and it is horrible. There are four places on the original Brush Bar that do not have bristles...the one I bought has them and when the brush bar rotates it hits places on the bottom plate...even after I tried to cut the bristles off.