There are 2 types of installer within:https://www.kaspersky.com/small-to-medium-business-security/downloads/internet-gateway?icid=gl_sup-site_trd_ona_oth__onl_b2b_klsupport_tri-dl____gateway___ 

1. Version 6.1.0.4762 | Red Hat Enterprise Linux | Localization package
2. Version 6.1.0.4762 | Red Hat Enterprise Linux | Distributive

What' the difference between these two packages?

Localization package is something you install additionally after installing distributive (application package) to get the local language (for example, Japanese).
You can see the order here:
https://support.kaspersky.com/KWTS/6.1/ja-JP/174936.htm
There is no help page for "Installing the localization package" but it's just 'rpm -i'.