Review on High-Quality Haobase 50pcs Mixed Colour 5mm LEDs Pre Wired Light Bulb - Bright 12V 20cm Mini Lamps by Elena Bryant

I ordered them as turn signals on a 12 volt circuit to run 24/7 but the problem with them is the built in limiting resistor is too small for the current to flow through the LED could pull . The resistor appears to be 1/8 watt (based on physical dimensions) and when I applied 12 volts the resistor got hot enough to touch almost immediately and the heat shrink started smoking in less than a minute. I haven't disassembled or measured any, so I don't know the value of the resistor or the actual current flowing through the LED. What I actually did was put a 1kΩ 1/2W resistor in series with the positive wire and bingo! No more heat issues and the LEDs are still bright enough. They might work fine on 3 or 5 volt circuits coming in, but if you're running 12 volts like me, I'd at least test it to see how hot it gets and/or add a larger wattage resistor, done as I did to avoid fire/failure issues before attempting your project a second time.