This is a very high quality rubber flooring. The edges on both the straight and the interlocking pieces are seamless; they fit together so beautifully without any gaps whatsoever. Very dense and durable. Exactly what we were looking for. We purchased black tiles in the 4'x4' size. Upon close inspection (while installing) there seems to be a bit of slight discoloration on some pieces that might be a product of the manufacturing process. It is very minimal and the floor as a whole looks great.