At Inzone we have 6 different handle types, and choosing the right one isn't always easy. Not all handles are available for all blades and rackets - eg. Flame Series is made for children, while Safe Series are made for adults, and both are only made with the recommended handles.

Here is a little information about the different kinds of handles:

STRAIGHT. The straight handle is completely straight, almost squared and quite thick. It supports a firm grip and usually best fits in rather big hands. For children this is rarely a good solution.
STRAIGHT (SLIM). The slim version of the straight handle is more rounded and supports a more loose and flexible grip. It fits most hands, but for men with big hands it could be too small,  and for children up to around 12 years of age it could be too big.
FLARED. The flared handle supports a firm grip, and fits the hands of most adults.
 
FLARED (SLIM). The slim version of the flared handle fits most children from 10 to 14 years of age.
FLARED (XS). The XS version of the flared handle fits most children up to around 11 years of age.
ANATOMIC. The anatomic handle is mostly used by men with big hands as an alternative to the flared handle.