Shifting voltage is limited by mosfet transistor. The only thing to respect is left side of circuit is low voltage, right side of the circuit is high voltage. The two resistor are pull up. They are not needed if you already have internal pull up. You can even delete left one if you only need one way shift. It work perfectly on my quadcopter to drive esc without both resistor. Here I used 2n7002. I had to plug the right resistor to drive servo motor because they do not have internal pull up.
