very brightful, good with 4,7 ohm and 3 watts resistor. Getting pretty warm, but OKgread product. but no 3W maybe 1,5-2WThese things are bright. Just watch out as they get very hot.If you want to run these off a 5v or 6v BEC, you simply have to solder them together in series. So I always buy them in pairs. Has been working fine for a few months.These are good when run of a 1 S pack. 4v is ideal. However, string three of them in stores and they work will off A 3S pack. Note that the different colors don't all give the same output in terms of brightness at the same voltage, so red red blue will be different than red red red.... They also get warm to the touch when powered by 4 V...Do not plug straight into receiver! Note input 2.5 to 3 volts. Why they put a servo plug on I don't know.NICHT DIREKT REINSCHAUEN sind wirklich hell. Mit 3Watt Leistung hat es aber nichts tun - sind ca. 1 Watt LEDslike the description says, it is SUPER BRIGHT!!!! really have to control the 3 volts really well, anything above and it just gets really really really bright, never look directly at it!Has a JR-connector but only accepts 3V. No other technical information are given. If you connect to your receiver it will be damaged. calculating a resistor is not possible without further information.??????? ??????????????? ? ???