3v light bulb powered by 4.8v. How??

I have two 3mm light bulbs. The spec of them are unknown but I m pretty sure it works on 3v-3.6v  without any problem.

I plan to use it for a r/c. Input voltage is about 4.8v (4x AAA).
Because they are not led, I don't know what is the max current limit of it. Thus, what value of resistor I have to use?