The size of this LED bulb is 194, T10 or 501 which are all the same. The bulb is usually used as sidelight. Built-in current limiting resistor and diode to protect the LED from reversed polarity + - installation (If you insert them into the socket and they don't light, turn them oppositely and they will light).

T10 Wedge 0.52 watt LED bulb replacement
Voltage : 12V DC
Long Lifetime up to 50,000hours                            
Environmentally Friendly (Pb-free)
RoHS Compliant
No. Of LED: 6 LED
Angle of Light Beam: 180°

For use in new BMW's, Audi and Mercedes require LED Decoders.