There are many differences between the Premium Mats and the Premium Extreme Mats. One of the first differences is the thickness, the Premium Mats are 8mm and 3/8" thick, whereas, the Premium Extreme Mats are 3/4" thick. The surface of the Premium mats is smooth, whereas, the Premium Extreme Mats have a textured top. The last difference is the size of the mats. The Premium Extreme Mats are a bit smaller than 4' x 6' at 47" x 71", whereas, the Premium Mats are 4' x 6'.