I am writing this to inform those that have the stihl Br 500,550, and 600. Please check your Back Piece for cracking and splitting. I have already had one warranty claim for a cracked back piece and today the whole think snapped. Broke right in half, upper from lower, at the two bolts that hold the springs to the back piece. I have already talked to one person that has had a crack in his and there may be others. My main reason of doing this is that stihl needs to redesign this piece and I am hoping there are enough of you out there that is happening to so that stihl will recall the whole back piece. The blower is wonderful, the best that I have had or demoed. However I can't be taking it in for warranty work every 3 months.