I was very upset at first because the brushes didn't seem to be the size that came with my iLife V3S vacuum but I kept playing with them until I realized that I'm doing it wrong. Each replacement brush has the letter "R" or "L". And under vacuum there is also "R" and "L". If you don't put the appropriate brush on the right side, they won't work! You have to make sure not to over tighten the screw or the brush will not be able to turn. You may have to adjust yours more or less as no two machines are alike. I've been using replacement for a month with no problems! HOORAY!
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