This stimulating 6" effect wheel is a little more expensive because it is glass with multi layers of free flowing oils captured inside. The layered blue & greens liquids drift over one another continuously creating calming free-form images, like an ever changing ocean. Exceptional for visual stimulation, focus, and to promote or stimulate speech, colour and shape recognition. Can be utilized for conversation and reminiscence or memory exchanges. Choose From: Calming Ocean, Setting Sun, Lilacs & Posies, Original (multi bright colours), or Northern Lights (Subdued Multi Colour)