Host for single 21700

I was recently looking of building a new light using a 21700 cell for better battery life. Can someone recommend a host and maybe also a cell?
Thanks in advance

That’s pretty broad. Maybe you should specify what kind of light you want this to be. Flooder? Thrower? Do you want a tube light or a light with a larger head? Do you have a driver picked out? If so, what size is it?

I have a convoy c8 and I am pretty happy with the form factor and also with the light it produces. I dont have a driver, yet, I planned on opening a thread on that in a few minutes. I also dont have an emitter yet, but I am looking for something that can do at least 5A, even if the light itself wont be run at 5A all the time.

The Convoy M21A is the 21700 version of the C8. You might consider it.