If you absolutely must use a retractable leash (which you shouldn't), please use one where the lead is visible. Otherwise, it visually disappears and looks like your dog is loose.
And you should never use one with a dog who is high energy or stronger than you.
@CorvidCrone Now i feel a bit guilty about my childhood thought of "retract dog!". (it was from observation, not practice, when small dog owners pressed the button on the leash and the dog went backwards)