Pickers are among the strange interfaces in the mobile. There isn’t a specific defined role for them. People use them in very different occasions. • The most important role of a picker is to facilitate and replace typing act on the keyboard in mobile devices. The small real estate of the mobiles makes it hard for user to type in their input (It is good to know the 40px is the minimum size of a button for typing on iPhone interface). • Selecting is easier and faster than typing. Specially in the call to action’s page. • When there are multiple inputs using pickers will let you have different combination choices. • Make sure to have the size of the picker large enough for fingerprint or gesture touch.