Yes, sorry for the confusion of my question.
I thought it served the same code for both, regardless of the multiple-choice factor.
But his indication was perfect to find the code I needed.
It had been several times and select the checkbox documentation but I could not understand.
Now it works perfect for single or multiple value select and checkbox.
<?php
if( in_array( 'red', get_field('colors') ) )
{
echo '<span class="red"></span>';
}
if( in_array( 'green', get_field('colors') ) )
{
echo '<span class="green"></span>';
}
?>
Thanks for your help