Waterloov^® and how it works.

Rain water  flows onto the top of the gutter protector to the front of the panel and then down the front vertical surface of the protector.  Many gutter covers have solid tops and to this point work work very much the same.

The difference is in the water collectors. Where most other gutter covers, primarily the helmet type, contain only one long fin, that can let in large size leaf debris, Waterloov^® has a face with two rows of discriminating louvers that limit the size of debris and collect all the water without overshooting.

The small amount of debris that manages to get through the louvers is  washed out because the design of the louvers causes a swirling action at the bottom of the gutter as shown in the video. 

One additional benefit: Waterloov has a protective wall approximately 1/16" in height at the bottom part of the lower row of louvers that keeps debris from being blown or washed into the gutter. No other product gives you this protection. Others have a trough here that can trap debris.

Click for more detail on how Waterloov works.