What is frostblast dot damage increase by 10%.?

Frostblast are the grenades that are available to the sapper class along with the traditional grenades that you can choose from the available grenades like frag, concussion, sticky mine etc. To use them just tap on the grenades icon on screen. Once you have used a frostblast grenade it took 5-6 sec to use them again. I use them most of the time first I put sticky mine near the turret and then frostblast grenades If I saw opponents coming towards me.