WP_model-events.php

<?php
Class Product extends WP_Model
{
    ...

    public function saving($model){
        echo "The save method has been called, but nothing has been         
              written to the database yet.";
    }

    public function saved($model){
        echo "The save method has completed and the post and it's    
              meta data have been updated in the database.";
        echo "The Model's ID is". $model->ID;
    }
}
$product = Product::find(15);
$product->color = 'green';
$product->save(); // Triggers events