From the Manufacturer

The Raimondi Tile Leveling System was developed to overcome the common plague that has baffled many DIY and Professional tile layers alike; the problem of uneven tiles, aka “tile lippage”. This system of interlocking leveling clips and wedges ensures that your floor will be level from one tile to the next, and it also prevents tile for settling and warping as your thinset cures. The RLS system is easy to learn and you’ll also enjoy the increased tile setting speed you’ll be able to now achieve. But most importantly, the RLS system will help you achieve your dreams of a perfectly flat tile floor and you’ll absolutely love the results!