I've always gone for the FK series over ZA, just don't like how the ZA sits in my palm. Some people love it though, so as always, you need to find what's right for you. Zowie make amazing shapes but these mice are getting outdated. Still good choices and a lot of people swear by them because they're tried and tested, but not really something I recommend these days unless you really love the shapes. Listed as 5 buttons because you can only have buttons activated on one side at a time, but yes, it does have side buttons on both sides.
|Grip Width||5.55cm | 2.19 inches|
|Hump Width||5.75cm | 2.26 inches|
|Length||12.3cm | 4.84 inches|
|Height||4cm | 1.57 inches|