Built for use in arctic climates, cold assault battle droids-or "snow droids"- were built on an enlarged B2-series battle droid chassis but with their wrist blasters removed to accommodate the snow droid's greater grip strength. The heavy blaster rifle that replaces the wrist blasters was a more dangerous weapon, but the droid was still extremely effective even when it lost its main armament.
The major design flaw of the cold assault battle droid was that its large feet--designed to keep it stable on snowy ground--slowed it significantly when running.
Saesee Tiin encountered some on a mission to Diado during the Clone Wars. With the help of thief Na-Jia, Saesee Tiin was able to destroy them and the entire droid forces using a stolen CIS-Advanced starfighter, liberating the planet from the CIS.