Thunder Hammer and Storm Shield

A Thunder Hammer uses the same rules as a power fist. In addition, all models that suffer an unsaved wound from a thunder hammer and are not killed will be knocked reeling, reducing their Initiative to a value of 1 until the end of the next player’s turn. Against vehicles with no Initiative value, whenever a thunder hammer inflicts any damage result, it also inflicts a crew shaken result

A model with a storm shield has a 3+ invulnerable save. A model equipped with a storm shield can never claim the +1 Attack bonus for being armed with two close combat weapons in an assault.