A:Answer I am not sure, but it's bigger by about half an inch (maybe less) on the 3 sides on a Surface Pro first gen, it fits like a glove on the Surface Pro 4. It's been a great keyboard and when they remade the replacement they did some nice user upgrades, key pad response, better construction on the covering, and the touch pad is much better than the first keyboard that came with my surface pro 4 originally