Complex sentence: The Natural Ergonomic 7000 keyboard has the same key layout as the Natural Ergonomic 4000 with the biggest difference being that the Natural Ergonomic 7000 keyboard is wireless.
Split into simpler sentences: The Natural Ergonomic 7000 keyboard has the same key layout as the older Natural Ergonomic 4000. The biggest difference between the two is that the Natural Ergonomic 7000 keyboard is wireless.