This is my second GL4.  The first lasted about 10 years but the gel finally evaporated out of the pad somehow.  It has been the absolute best solution for my needs.  This new pad is equally as good.  I do notice the velcro tape which holds the gel pack to the mousepad is about an inch further up the pad than the original which was attached right at the base of the mousepad.  This results in a one-third smaller surface area than a normal mousepad when using a mouse.  Doesn't bother me as I use a Kensington Expert Mouse (large trackball).  I suppose this was done to keep the entire gel pack sitting on the mousepad itself.