Can I use an LED replacement bulb in my 14.4 volt rechargeable flashlight? And what is the difference in the bulb types?

You MUST use the appropriate LED cartridge for the voltage flashlight you have. 14v is very high and you will likely need the exact kit for that light. What brand is it?

What bulbs are you asking about?

The flashlight is a craftsman from a kit with a rechargeable battery. I haven't been able to find a bulb in stores for it and wondered if any LED bulbs were compatible.

Well they certainly are not generic. You would have to take the burned out lamp with you and try to find an LED retrofit for it.

Sears carry's the proper replacement bulb.
You can even order a couple on line.
For my craftsman 19.2 volt flashlight I went to radio shack and got a 20 volt bulb and it's lasting for a long time so far.
Some how a freshly charged battery makes the bulb burn to hot and lasts a short time. The 20 volt bulb is still plenty bright for crawling around in an attic.
The link I wanted to give you is down right now...