Cyanogen MOD in android devices

CyanogenMod is an aftermarket firmware for a number of cell phones based on the open-source Android operating system. It offers features not found in the official Android based firmwares of vendors of these cell phones. It is actually similar to firmware updates.

Features :-
1. Gesture Lockscreen feature.
2.Phone goggles- which filter its outgoing communications and avoid any unwilling call or SMS to be sent
3. Themes Support 
4. Great sound equalizer.