T4.2 1 3528 SMD LED Light Bulb. Use this T4.2 LED Light bulb to replace lights in instrument panels. 12 Volts D.C. The LED Bulb has one 1210 (3528) SMT LED. This product measures 0.38 inch by 0.33 inches. Up to a 6 Lumen output. Comparable to a 4 to 9 Watt incandescent light bulb.