Voltage step down for lavalier mic phantom power?

Does anyone know what is involved in doing a circuit to use 48v phantom power with a lavalier mic that takes (I was told) 6-7 volts? Here's an example of the kind of thing that is used for some mics.
https://www.ebay.com/p/Cardioid-Lavalier-Microphone-48v-Phantom-Power-Adapter-for-Shure-Mixing-Console/1856600904

I think it's something similar for the Countryman lavalier mics:
https://www.bhphotovideo.com/c/product/295908-REG/Countryman_B3P4FF05B_B3_Omnidirectional_Lavalier_Microphone.html

Is this thing -- which fits in a small shotgun shell sized case -- DIY-able?

Any insight appreciated!

You "were told"?

Either way, those lav mics are just small electret capsules. See the other thread for details.