php - How to get the page arguments from URL in drupal 7 -

i have created on menu hook in drupal 7

$items['assistance/product-help/%'] = array(        'page callback' => 'product_water_serach',    'access arguments' => array('access content'),        'page arguments' => array(2),        'access callback' => true, ); 

my url

http://example.com/assistance/product-help/abcd+%20test 

my function

function product_water_serach($product_name)    {      echo $product_name;     } 

output : abcd test

my requirement output should : abcd+ test

kindly suggest solution above.