This one has a screw back so you have to use a few different special tools. Here are a few links to open the watch with each tool.
http://www.esslinger.com/howtoopenascrewdowncaseback-jaxawrench.aspx
http://www.esslinger.com/howtoopenascrewdowncaseback-caseopenerball.aspx
http://www.esslinger.com/openingascrewdownwatchcase-casewrench.aspx
Luckily you have different options. Good luck with your watch!