Just two little bolts, you can see that the little edge put in place by Unger doesn't stop the belt, the belt can still freely move, and misses the plastic edge by about 2mm. I found this very very annoying, because my belt went all over the place, especially with my thick winter coat moving it around. Just make sure that you place the bolts at the correct distance so you can still move the boab around a little bit. It's really up to your own preference.
I tried emptying the bit of water that's left in there with the applicator, and you just have to tilt your actual belt a bit as well. No problem in that regard.
Along with a blade protector it makes a much better boab. (Bucket on a belt)
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http://www.cleanitup.co.uk/smf/index.php?topic=29445.0 )
*sigh, the things you have to do to have space for another squeegee, the original is the better one in my opinion*