This is a Vidal Sassoon curling iron. It's over 10 years old ⭐︎ There's no manual, and it's probably 32mm☺︎ You turn it on and adjust the temperature with the dial. It's ready to use when the on/off light stops blinking and stays on. There's a crack in the black plastic part where you clamp the hair, but it still works ^_^ #hair iron #curling iron