Bought for an old Shark Ion Robot that lost its brush, the battery life was terrible and I was about to throw it out. I recently bought a BObsweep and it was awful, always stuck, got lost and found its way home twice after 50+ uses. So I bought a newer Shark model with the auto empty tank and fell in love with it so I thought maybe I should try fixing the old one and use it on top. WHY DID I NOT DONE THIS BEFORE? My old sweeper works like new again, so does a good job on top while the newer Shark takes up more space on the bottom. This set was worth the money!