and high quality. Heating side is empty. Red wire to positive, black wire to the negative, it generates electricity when the temperature difference happened Small and lightweight, convenient for use. Designed specifically for power generation. Sealed for moisture protection and contain thermal elements formulated for optimum Seebeck power generation. High temperature 150°C, with NM static protection. Temperature electromotive force (a): 190x Greater than uV/ C Optimum value (Z): 2.5 ~ 3x10-3W/ OC Model: SP1848-27145 Working Environment: -60~125 degree Lead Length: about 30cm Thermal conductivity (K): 15~16x10-3-W/ C cm Conductivity: 850~1250 Omega -1.cm-1 Product Name: Thermoelectric Power Generator Product material:ceramics Product color: white Product size: 4cm×4cm×0.38cm Product weight: 92g Package Contents: 4x Thermoelectric Power Generator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.