INSMA 10PCS 40x40mm Thermoelectric Cooler Heat sink Power Generator Peltier Module TEG 150 Degree High Temperature Chip Small size,Light weight, long life No moving parts, easy to move High reliability and no pollution 40*40mm Thermoelectric Power Generator Peltier Module TEG High Temperature 150 Red wire to positive, black wire to the negative, it generate electricity when the temperature difference happened