Best way to make the user select a time?

Hi I'm wondering what is the best way to make the user select a time, I already have the user select a date with a calendar but then needs the user to select a time to be able to create a date based notification. What is the easiest way for the user to select time? Should I show another VC when the user selects a date to show a clock or show a date picker with time showing? Are there any other ways?