The SIZE, above all was important as were the ridges on each slat ot teak to eliminate slipping.  Lovely piece of work and looks so nice in he bathroom.  But the utmost is the safety of not having to trust slippery mats and continually straightening them out to look neat.  The rubber feet on the bottom are very helpful and the open edges on the long ends assist in drying out the area under the slats.  Good product, well designed.  Kudos!