Cobalt blue ceramic oval tab. Size: 1 1/8 x 1 w x 1/8. Directional energy is emitted from their underside. Three strengths. Tab (bottom) appropriate for most machines. Toroid (middle) when there are several machines in the vicinity, or the emissions are very strong. Tri-hole (top)for very strong currents such as water heaters. Cleans and neutralizes harmful and negative energies in the environment. Also good to place among your crystals and stones; energizes plants.