What needles work the best for liners and shaders?

I am learning how to tattoo and I want to know what needles are better for liners and shading? What is the difference between the round and flat needles?

good ones. preferably from a reputable company that won't sell to you.

good ones. preferably from a reputable company that won't sell to you.

good ones. preferably from a reputable company that won't sell to you.

good ones. preferably from a reputable company that won't sell to you.

see how i posted it many times? get the point?