A roller mixer is ideal for gentle mixing action. It consists of a number of motor driven rollers which rotate at either a fixed or variable speed. When the samples are placed between these rollers samples, typically in tubes or bottles, are rolled gently. During this rolling action, simultaneously a rocking action is applied whereby the rollers are gently raised and lowered at one end. This increases the effectiveness of the mixing whilst still providing a subtle action. Ideal for mixing blood samples, viscous substances and liquid-solid suspensions where minimum aeration is required or for aiding de-frosting of samples.