work in 9-12Volts Do not need add any resistor, it can work in 9-12Volts directly Specifications : -Size: T1 Round (waterclear) LED or 3mm Round (waterclear) LED Brightness: 2000-2500MCD -Emitting color: Amber -Wave lenght: 580-590nm -Forward voltage:9V~12VDC Compatible. -Forward current Typical: 15mA or below; Max: 20mA -Viewing angle: 25-35 Degree- Applications & Installations Ideal for 9-12V LED replacement for computers, radio, dashboards, or any battery or power supply that the voltage in 9-12V .etc. Very low power consumption, and high luminous intensity Recommended voltage is 12V Package included : 50pcs T1 Round (waterclear) LED or 3mm Round (waterclear) LED(Amber) Search ”bowerful ” for more related leds;