Hand Mixers For a perfect dosing result Hand mixers in the form of hand stirrers or vertical-motion agitators are used in dosing technology to mix a dosing solution quickly and smoothly in the chemical supply tank. Whether a hand stirrer or agitator is selected depends on which form of operation is preferred. A vertical-motion agitator permits higher manual energy input, while hand stirrer is adequate if the substances to be mixed are soluble.