This makes the FL!PPER safe to use at the sand level for the majority of sand sizes, and prevents sand from being caught between the the magnet and the glass. If you flip the FL!PPER over, you then have the convenience (or inconvenience?) of the scrubber side. This side should never come into contact with the sand, or in fact get anything caught between it and the glass. There is NO gap between the scrubber and glass.
The FL!PPER cleaner also floats! So while manoeuvring it across the glass, or changing from side pane to front pane and loosing magnetic connection, instead of having to retrieve it from the aquarium sand bed, it will float up to the surface where you can grab it.
Have a look at FL!PPERs website here